Moderators should have the right to choose who participates on their forum

You can, as long as you follow the saidit mod rules. We want to avoid echo-chambers here, because that's what destroyed reddit. If your ideology is so weak it cannot tolerate any questioning or differing opinions, then it's not a very good ideology.

But the only people who have been systematically denied that privilege has been conservatives.

False. And when you try and deny others their free speech based on your victimhood, you're no better than those you claim to despise.

We have higher standards here on saidit for free speech and open debate, and we will not allow you to censor others simply because you got yourself in to a mod position. These are the rules. https://saidit.net/s/SaidIt/comments/w6s/saidit_rules_for_moderators/

All you have to do, is tolerate dissenting opinions. Not asking a lot here.