Is it possible for religions not to criticise other religions?

Answer 1

No.

Well, yes. Buddhist leaders do not criticise other religions.

It is not the religion which criticise other religions, but the people of those religions. If another religion is in conflict with the teachings of their religion, then the other comes under some criticism. As a thought the criticism only effects those who do the criticizing. At times the criticism may also be warranted and may help to warn others and disclose truths which some would prefer hidden. If all members of all religions would be both perfect and completely open and honest about themselves and about where they stand, then there would probably a lot less criticism. It is not only those who do the criticizing who can be harmed, sometimes those who do the criticizing have legitimate concerns, based on facts which need to be aired and disclosed. Some cults in particular deliberately use terminology with which people are familiar and then change the meaning to suit their theology. They then do not tell people they have done so and pretend to be orthodox when they are not. This is indeed deserving of criticism. And since Christians in particular are concerned with truth they rightly find such behavior offensive.

Having said that, the above er is certainly correct in referring to what some would call 'internal criticism' where people are attempting to correct their own brethren in their religious group. Family members can be most frank with each other at times. Sometimes it may be for good and sometimes not. The intent always ought to be for the good of the other, to bring them back to a right path.