Certainly all religions may offer things which are both beneficial as well as harmful to people and societies, but is there a one true religion? How can we know which religion is true?
If by trying to find the one true religion our search involves investigating peoples sincerity, then we shall get no where, for every religious person out there will swear to you they have the truth and may sincerely believe it. How people feel about something does not constitute evidence. Someone may "feel" they have found the one true religion, but another person from a different religion may equally claim the same thing, with equal amounts of certainty.
When all is said and done, all religion really has to offer as evidence are its holy scriptures of choice. Books which were written thousands of years ago. Yet one must ask- if religious scriptures like the Bible did not exist, how would those religious people discover the truth about life, death and everything?
Compare this with spiritualism, which offers a large quantity of evidence in many different forms- Near Death Experiences, EVP, Apparitions, Physical Mediumship, Mental Mediumship, Hauntings, Video and Photographic evidence and so on. Say what you will about the quality of the evidence, but there is at least, a large quantity of evidence to be investigated. Evidence that is not simply from one period in history but from which phenomenon can be found far back in human history up to the modern day, in all corners of the world.
What this tells us is that in pursuit of truth regarding spiritual matters, one has the choice between blind faith that religion has to offer and examining a very large base of modern and historical evidence to be found in Spiritualism.