Because there is ignorance about what Spiritism is. Although we are in the middle of the 21st century, with countless books at our disposal, the Internet, CDs, DVDs, movies, television, etc., when speaking of Spiritism, many still fear and criticize it, and although most of today's monotheistic religions worship the same deity, many religious are unable to accept, or only live peacefully, with people who do not follow the same beliefs and dogmas.
José Herculano Pires, addressing the prejudice against Spiritism, in the book The New Man , points out that anti-spiritist prejudice seems to have occurred against Christianity in the ancient world, in the sense that people who fear and do not know the Spiritism gives it improper applications, getting lost in a tangle of legends and assumptions about the spiritist sessions. Normally Spiritists are accused of demonic, necromancer, sorcerer, among others, just as the Greeks and Romans did to early Christians.
Remember that these misrepresentations of Spiritism are not only oral, among simple people, but also in scholarly publications, magazines, newspapers, essays and studies, with cultured signatories. The author also brings the opinion of Pythagoras, stating that the earth is the abode of opinion. And being opinion a frivolous, uncertain and irresponsible thing, it is no wonder so many people give their opinion about what they do not know, and this is a habit that exists even among the most intellectual.
However, when it comes to a spiritual doctrine, advocated by so many educated men, of projection into the world of science and thought, people around the world, of culture or even of average culture, should be more careful in positioning themselves. respect, because if the right to opine is free, so is to judge the sense of responsibility of the opine. According to José Herculano Pires, the greatest reason to fear Spiritism is human cowardice, which makes men shudder with fear at the danger of changing their opinions before the world and life, when Spiritism changes the narrow conception of a false life, for a broad conception of spiritual life, deep and true.
It is from the natural logic of the critic that he, in speaking of something, knows him thoroughly, not superficially, a situation in which his opinion would be of no value. Kardec emphasizes the need to study Spiritism deeply so that any criticism of value can be issued. In the book What is Spiritism , the Codifier, in dialogue with a critic of the Spiritist Doctrine, who wished to write a book about what he considered a mistake, states that to deal with an ex professo question, it is equivalent to say that it was studied from all its faces, that everything was seen and read about the matter, with analyzes and comparisons of different opinions, that is, nothing was neglected to reach the truth, because only the one who does all this can say who speaks knowingly.
Spiritism respects all religions and defends freedom of conscience, a natural consequence of freedom of thinking, patrimony of man. It understands that every belief that encourages and educates the human being to do good and not evil is respectable. Religion, however, cannot be used as a mechanism of persecution or imposition, for belief when imposed does not develop man's true values, sincere faith, and love.
Let us remember the wise and fraternal words of the late Chico Xavier  who, by participating in the Tinga Pinga Fogo Program in 1971, addressing all religions and miracles, points out that all the religions that make the good man are good and are instruments of man's connection with God. He said that all phenomena of divine goodness, such as brought about by the Catholic Church, considered by him as the mother of our civilization, are legitimate and, therefore, creditors of our veneration, emphasizing that we are not separated, the reformist evangelicals and the spiritists. Christians for fundamental differences.
Informs that the spirits teach that, although we are all in different ranges of interpretation, we are a family only before our Lord Jesus Christ, which is why we reverence the Pope in his holiness and the eminent cardinals in Brazil, protectors of our faith. He stresses that man cannot forget this fact and that he loved the traditional religion in everything that is beautiful and divine, even if it followed in the range of Christian Spiritism, within the conceptualizations of Allan Kardec, because of the mediumship that had called him to this field of work, also deeply Christian.
Chico asserts that religion is always good when founded on the principles of goodness, because it makes men good and is a process of connection with the divine forces emanating from God. It clarifies that all religions that object to the chiseling of the human creature bring authentic peace and love, without any offense or disregard for anyone, being a holy path that Christian spiritists respect and must respect more and more.
It is precisely this feeling of brotherhood and brotherhood among religions that must exist, we must all seek to live in peace, working for the growth of humanity, founded on the love and living of the Gospel of Jesus.
Spiritism relates to other religions in a quiet, serene and respectful way, because it understands that just as Spiritism can lead, depending on its use, people to "heaven" or "hell", that is, to have in the physical and spiritual planes a happy life or suffering and pain, the other religions can also. It will all depend on how they will think and act after studying and practicing these religions.
Spiritism is a doctrine always open to coexistence and dialogue with other religious beliefs, based on a broader understanding of the moral teachings of Jesus Christ and the Natural Laws clarified by Kardec. It is not essential to follow one religion or another, but to understand God's Natural Laws, to act ethically and morally, based on the principles of equality, fraternity, justice, and love of neighbor, as so well presented and experienced by Jesus Christ. .
Therefore, it is not the fact of being a spiritist, the frequency in temples, the multiplicity of words, the observance of rituals and dogmas that elevates men, but their intimate reform through self-knowledge and the search for self-enlightenment, is the practice of Charity through love in action. This time, religions and other philosophies must, as I said elsewhere by Chico Xavier, transform man for the better, that is the great challenge of all beliefs.
These remarks are not intended to discourage rituals in temples. In fact, it is all part of the path of spiritual elevation, and if one really thinks and desires goodness, is positively vibrating for oneself and one's neighbor, and seeks to be a good man, one will surely be “saved,” regardless of the religion that one has. follow.
 PIRES, José Herculano. The young man. 3 ed. São Paulo: Spiritist Fraternal Mail ABC, 1989. p. 14
 KARDEC, Allan. What is Spiritism? 56 ed. Brasilia: FEB, 2013. p. 44.
 YOUTUBE. Chico Xavier talks about religions and miracles and their visions. Available at: <https://bit.ly/2Nn1XUE>. Accessed on 11 Jun.2018.