The intolerance that many trans-rights activists show to those who don't accept that a man with a 'female gender identity' is a woman is similar to the intolerance that many followers of Islam show to non-believers.
No-one on the gender critical side has been beheaded yet, but there is a surprisingly large "kill the terfs" movement that parallels the extremism of Islamists.
Let's put this whole subthread in perspective. Someone told a story about how they "got scolded" and then two replies later the conversation has drifted to the idea that LGBTQ don't exist, their movement parallels one of the most inflammatory boogeymen you can use in US political discourse, and the only reason they haven't come for our heads yet is because they aren't powerful enough. The conversation usually drifts from here to "Well how do we stop them from getting power?", at which point it gets really ugly. It's a subtle move from "these LGBTQ don't even exist" to "these LGBTQ shouldn't exist", and unfortunately we've seen the consequences of that kind of thinking more often recently. The usual solutions are: make their existence illegal through the political system we control, or exterminate them with violence.
And this gets me back to the defense mechanism. It's unfortunate, I agree. In a better world there would be room for nuance and polite discussion to foster understanding. Unfortunately in the real world, things go really quickly from a misunderstanding to actual violence. The real kind, not the suspected kind. So to prevent that real violence, you get a "nip this at the bud" kind of responses to things that may be benign or just a misunderstanding. Unfortunately deadnaming and misgendering are followed often enough by violence, that even when it's not intentional the response can be harsh. The sad part is that this way of interacting is not productive for anyone, but survival mechanisms are usually a last resort, not something meant to be polite.
It's like if someone said the Elon Musk is bad because he invested X amount of money into Y, and I'm better because I didn't (suppose I'm broke and I spend my days in a basement playing games). The "I'm better part" is flawed because we don't know what I would do if I was given his choice.