If you think an ideology or religion is immoral and evil, should you actively oppose it?

[LogicalFallacy]

Quite possibly.

[Aries256]

When they are not harming others, no. Live and let live. When they are harming others, yes I believe it is something to actively fight against. 

[VerbosityCat]

I don't think so. You can use up all your energy in this life "opposing things", then you aren't actually creating anything to add to the world. My life is worth more than "opposing things" and "fighting things". I and everybody else has the right to live their life FOR a purpose rather than constantly in opposition to something else. The existence of evil is not an obligation I must address. That to me is too similar to the christian idea that thinking a bad thing is just as bad as doing a bad thing. No, it is not. These kinds of "purity spirals" put people in bondage to "obsessive goodness".

[VerbosityCat]

This line of thinking also presupposes that somehow I am morally obligated to "correct" other people's wrong thinking or wrong behavior. This is actually part of why there is so much unnecessary conflict in the world to begin with. Everybody thinks they are right. And when you are sure you are right, then somebody else must be wrong. And that wrong opinion/viewpoint/action must be "fought". I'm not saying there is never any time for fighting. That would be absurd. I definitely believe there is a time for fighting but most people have a hair trigger in this regard and think it is their moral duty to "fight and oppose" everything. Well who asked them? Half the time all these things people are "fighting and opposing" aren't even things that are objectively wrong, just things the "fighting" person THINKS are wrong. Imagine if people stopped opposing and fighting EVERYTHING that they thought was bad, and instead saved their energy for fighting the bigger shit.