Looking for opinions on how to moderate a community

Hello.
I moderate a reddit sub with about 450 thousand people and we have had trouble with transgender people facing abuse from idiots in two different threads. In one of them, a woman chimed in and it got ugly (4 bans in the first 12 comments), in the other a trans woman took part and got shit for it (also featured a few users banned).

Now, each of them had a very different approach. The first got defensive and stopped participating, while the second took the time to respond to the stupid but not offensive ones, trying to educate them.

So even if this is something that bothers me a lot and makes considerably angry, I realised that maybe I should take a more nuanced view on this, and I should actually ask for more opinions on how to handle thiS, instead of simply applying my own standards and maybe making things worse and/or missing a chance to make things better. And since Tildes has always provided me with intelligent, thoughtful and interesting points of view and opinions, I thought this would be the best place for this question.

And so here I am, asking anyone that would care to give an opinion: what would a good moderator do? How harsh or lenient should we be with ignorant but not offensive comments? Should we get involved at all if the discussion is not offensive? What would make our sub a nicer place to everyone? Any other thoughts?

Thank you very much to all.