Why religions (including Christianity) can often cause more bad things than good?

Because all these religious people (but IMO especially Christians) kept preaching one thing, but then DO the other (contradictory) things. Like for example, Christians often talk about Love, Love, and Love,
yet I too often saw THEY are the ones who are the most judgmental, passing judgments into other fellow human beings, playing god themselves, condemning others, alienating other fellow human beings, and in general due to their narrow mindset (ie: because they only see and hear “what the Bible said”, and don’t CARE about any other things in this world!) cause so much hatred and at the worst case wars.

I even saw many non-religious people (ie: atheists, agnostics) who really show real, compassionate LOVE & did many touching good deeds in their daily life,..without any narrow mindedness and passing judgments and “following what my Holy Book said” as if like robots who have to follow their manual/instructions, instead of pure AUTOMATIC loving.

Religions could be a good thing, ie: it teaches some good morals, humbleness, be kind & generous to other fellow human beings, love & taking care of Nature,
but it’s very very sad sometimes to see/witness of how so many people (a.k.a human beings) just look for the trees instead of the forest, place too much importance on the differences in the doctrines that makes them “different and special” than other religions, thus causing hatred & wars.

Why is this?
Why religions can often, in reality (not “theoritecally”), cause more bad things than good things?
cause more hatred than love?
cause more passing judgments, instead of showing full, selfless LOVE to other fellow human beings?

It seems that even John Lennon in his song “Imagine” knows (envisioned) what real, true LOVE is, better than so many so-called “religious” people!