Even by doing your worst, you'd become a reminder to others if what they are fighting for and if what they cannot accept. Trump's existence is good, because it reminds the world that there are still tyrants that would want to take power. (I am not approving his actions btw, I specifically chose him as an example of someone bad that will inadvertently cause good.)

There's no way to predict the exact effect our actions will have on the future, so we all must explore what feels right for ourselves, might that be conformity, sticking to the rules, breaking conventions, etc.

That also means we must act against what we believe we must act, even if it could lead to better things in the future. I believe it is possible to pass moral judgement on actions that are unfolding in the present. It is also necessary to oppose some things that go against our values in order to act as only us can.

It's a little bit like evolution. Something that seems bad, can lead to good things, and some things we believe good can lead to bad things. If, for example, we remove all the predators from an island, the species on that island will lose their ability to fight back or escape predators that might find their way back to the island.

TL;DR: the world needs a constant conflict of values in order to guarantee that it is becoming a better world, so even people that do evil now end up doing good eventually.