As long as you have the ability to NOT interact with them, via blocking or simply ignoring them, what’s the problem?

Because it lets people advocating genocide further their agenda of actual genocide? There's a saying in germany "If 10 people sit at a table, and they allow a Nazi to join them, you have 11 Nazis at the table". Making room for genocidal rhetoric is supporting that genocidal rhetoric. We're not talking about "bad opinions" here, we're talking about actual, literal genocide.

And here is a big problem - currently any and all questioning of trans and gender ideology is shouted down as “transphobic” and “wanting to eradicate trans people” by the far left. Should that all be banned?

If by "questioning of trans and gender ideology" you mean "advocating that trans people should not be allowed to exist, by denying them the therapies and procedures they need to transition", then yes - because that is advocating for the eradication of trans people - not by murder - sure, but by ideological suppression. If instead you mean things like "I have no desire to change my own gender" or "I don't really understand why someone would want to transition", then no - of course not.

And because I've interacted with enough concern-trolls like you to know what you're going to say next, yes - the exact line can absolutely be fuzzy and subjective - I've already said that, and I don't pretend to have a nice neat solution to the issue, but you don't need to have a solution in hand to point out a problem. That's why the point of my comment was centered around the fact that we should (though clearly you disagree) at least be able to agree that literal, unambiguous genocidal rhetoric, such as that professed by Nazis is something that shouldn't be tolerated.

The fact that you disagree with that point so strongly tells me all I need to know about you, really - and because this is - in fact a free platform, where we're all free to engage or not engage with whoever we want - I'm going to go ahead and disengage with you - because, like the lady who originally brought up this point - I really don't want to waste time talking to Nazi Sympathizers (or people who spend an embarrassing amount of time on this site arguing about what gender other people prefer to identify as, and whether or not that identity should be strongly linked to what's in their pants)

Can you give a few examples of what kind of speech you think should be tolerated that is not? And do you believe that communities should be allowed to make explicit rules against certain talking points? What stops you from making a discord server or your own instance to discuss whatever these topics are? Why does everyone else should have to read it?