I don’t think it’s necessary or required to be nice and polite all the time. There’s no such thing as a polite revolution, even if there should be. But the idea that tone does not, or should not, matter when you’re defending a cause is 100% bullshit. In rhetoric, tone matters. It’s not just what you say—it’s how you say it.
Shouting “Trans women are women” won’t convince people who aren’t familiar with how gender identity works—and it definitely won’t convince people who are right-leaning or centrist but are open to listening to either side. Yelling at them will send them into the arms of transphobes like TERFs and fundamentalist Christians, who reinforce their preconceived notions about gender and sexuality. Your average person is extremely unlikely to be trans, and they are also unlikely to know a trans person, so treating these arguments as truisms does not help this just cause.
Shrieking to a pacifist or soft Zionist, or even your average person who doesn’t know much about the relationship between Israel and Palestine, that Israel is a settler-colonialist imperialist project will merely shut them down. They don’t know what the hell settler colonialism is, and they may not even think that “colonial” is a bad thing—after all, brand names like “Colonial Window Company” and “Imperial Margarine” are common in the US. “Settler colonialism” is an academic talking point. If you say that you don’t care about Israeli civilian casualties or hostages, you’re not going to bring a single person to your side. You just look like a heartless supporter of terrorists (which you are—ironically, you sound a lot like the hard Zionists who will happily bomb the shit out of regular Palestinians to get Hamas). If you call Hamas a bunch of freedom fighters when the news says they’re terrorists over and over again, then they’re not going to listen to you. They’re going to look at you as though you’ve grown two heads. There is a reason why the mainstream media has no time or reason to listen to anti-Zionists: it’s because you keep undermining a good cause (ending the Israeli apartheid regime and stopping Netanyahu’s barbarous attacks on Gaza) by demonstrating a lack of empathy, consideration, patience or basic decency. I am furious at most of the anti-Zionists I’ve spoken to because they’re being heartless assholes. I despise Netanyahu. He’s a genocidal creep. I think Israel’s actions toward Palestinians have been abominable. But Hamas is not the answer. They’re slaughtering civilians. Through their indiscriminate violence they have undermined their own goddamn fucking cause.
I am against all sexisms, including transphobia. I am not a Zionist. If I didn’t already agree with these causes, either in whole or in part, I wouldn’t be convinced. In fact, I would probably double down because I was tired of being scolded over and over again. You cannot make your case by pouncing on people and yelling at them every time they fuck up, every time they merely repeat what the news has pelted them with for the past decade, every time that they ask questions and want to learn more. If you don’t have the energy to argue politely, find people who do. (There are some topics I can debate, like geopolitics, but I can’t debate LGBTQ+ rights, for example.) There is more than one way to organise. I can’t engage with homophobes and transphobes, so I refuse to debate them. There are other queer people who can do that. I used to in the past.
This is why you keep hearing right-wingers and centrists talking about “woke scolds,” even though these people are far from representative. (The worst scolds are on the right.) A jerk for a good cause is still a jerk—and most people will respond accordingly.