Of course, let's never discriminate, but that's it. I've never seen a merge request rejected because the author was gay, woman or black. Everything is correct here, there is no issue.
This is an overly simplified view of the world. There are systemic issues at play in society that lead to far fewer contributions from women and minorities, and there's also the problem of women and minorities being made to feel uncomfortable in spaces dominated by white, English-speaking men. These issues need to be considered; you can't just say "we're not actively refusing contributions so it's fine". More subtle bigotry, like not truly accepting the identity of a trans person, or accepting stereotypes about women and unconsciously using them to judge women, needs to be considered as well.
the LGBT/feminist fascism and superiority movements, manifesting e.g. in the form of COCs, which did result in discrimination and kicking people out of development, and which actually resulted in kicking Stallman out of the FSF.
This, right here, is an example of the sort of thing that drives women and minorities away. I've met a self-defined "trans supremacist", and they're
not anything like the LGBTQ+ community. Incidentally, they're also a white supremacist and enbyphobic.
It's ridiculous to say that RMS being kicked out of the FSF is the result of "discrimination". He is a
public figure who was the figurehead for the libre software movement. When you have the privilege of being a public figure with an elevated voice, you have a certain level of responsibility to use that privilege responsibly. RMS did not. For
decades, he's been saying problematic things that give the entire libre software movement a bad image, and frankly that many people do not want to associate with (myself included). He
chose to conduct himself in that manner.
Genderqueer people do not
choose to be genderqueer. Trans people do not
choose to be trans. Gay people do not
choose to be gay. And all the LGBTQ+ community wants is
acceptance and
basic human decency. We are not a supremacist movement. That is absurd.
Feminism isn't a supremacist movement either, with the special exception of TERFs, who most Feminists I have met (myself included) do not really accept as Feminists. TERFs are just transphobic male-haters and rightfully get just as much ire from the LGBTQ+ community as any other group of bigots.
respecting freedom of speech
When you dig deep, those who talk about "freedom of speech" are usually in white supremacist circles. Often unintentionally; I was duped into being in the alt-right circle for a couple years with tactics like that. But that's the core of it.
Also:
https://xkcd.com/1357/I don't think there is room for a cisgendered white mail proprietary Americans here.
No one has even asked you to leave. Being inclusive of women and minorities doesn't mean excluding cis straight white men.
I think that is a social skill deficit that also needs some tolerance, as long as it isn't repeated trolling.
Worst xkcd ever created, just for the record.
Calling each other fascists really isn't what I meant with keeping it civil. 
And I mean both sides of this.