Hi abcde,
The biggest critisism you could give a religion is that its beliefs are "wrong" and that God doesnt approve of them.
The only beliefs we know to be "wrong" in any religion are those which *in the action they produce* cause harm. So we can critisise if we see these beliefs causing people harm.
That is why it is justified to critisise the Jehovahs Witness view of blood transfusions, because it has harmed people and taken away their precious life. The views on blood have changed too, so those who died years ago neednt have died (which is proof of the falsity of the belief - it doesnt stand the test of time). Similarly other teachings of the JWs which cause harm to people can be assessed.
We can do this with any religion and be justified. People can believe what they want to, but if they ACT on their belief to the harm of others then that is wrong. If they promote others to believe it and THEY harm others, that is wrong.
Constructive critisism is needed. You should be open to it, and be happy that people care enough to point out where your beliefs may harm you.
Jehovahs witnesses, however, mostly critisise other religions on what they believe, even if that doctrine does no harm to anyone. They say that the believers of so-called "false things" will die at the hand of God. Surely thats the worse form of critisism?
Sirona