Prove it. Some religions actually are religions of peace, such as the Christian Quaker sect. Others are not the same.
It is a logical error to claim they are the same, is it not? And we know that different sects of Islam teach wildly different behavior. Again, they are not the same.
Here is my proof:
http://www.worldprayerfoundation.com/resources/World%20Scriptures.pdf
Read it and you will understand my opinion that all religions are religions of peace.
I am descended from practitioners of a religion that does not exist today, but those practitioners engaged in human sacrifice. Therefore you are wrong.
Perhaps what you mean to say is that "The religions left existing today, after we exterminated the other ones, all profess to be peaceful religions?"
But that is in itself an admission of religions being violent.
This may be of interest -
https://en.wikipedia.org/wiki/Religious_violence