You say you’re arguing in favor of less toxicity, but your example was a screenshot of a comment where I asserted my own healthy boundaries (after being needled by hundreds of demands in the form of “what about ?” from strangers over the course of months).

Which is more toxic?

The one that contains the most aggression.
Do most of those strangers know that you are receiving hundreds of requests? They're strangers, so I'm betting on no. Are they then deserving of any swearing and caps lock yelling? Even if they do know, I can recall few to no instances where unironically doing so packed a punch.

A more reasonable answer would have been: "Sorry, no idea. For my own healthy boundaries I have to refrain from doing too much of this often-requested but time-consuming research."
Not toxic, more effective. And as I mentioned in another reply, with AutoKey you could configure that typing the word "sigh" or phrase ''goddammit not again" automatically expands into the alternative answer suggested above. Being frustrated is fine, and venting is absolutely necessary, but there are ways to do it that are healthy for everyone involved, such as the autoreply and then going for a run. Hope for the best, prepare for the worst.

It seems like trusting the nicest voice in the room on a topic like security, rather than experts, could be a mistake

Because the inverse of that is how people get conned. Someone blowing absolute smoke with a confident tone and a sweet word. Tone is about the worst indicator of trustworthiness

Sure, skilled sociopaths con their way up that way, or that's how soulless marketers manipulate the populace. However, that does not mean that most people who are kind are sociopaths or soulless. On average kind people are just being kind.