It's strange hearing reports of "scroll lag" in the other comments. It's possible I'm just lucky. Or there's a misconfiguration somewhere in their setup that Chrome somehow avoids.
It's true that I still mostly use Chrome for webdev - I've become more used to it's (excellent) dev tools, even though Firefox and Firebug started that whole trend. It feels very right to separate my "user browser" from my "dev browser" in this way!
Don't forget the other possibility: someone using Firefox having internalized this lag as "normal behavior".
Have some humility.
I've known lots of developers who thought that some broken, slow, erratic, or stupid, program or OS behavior is the normal, because that's what they've been used to. They could be great programmers too, they just didn't venture much outside the stuff they used.
As for the diatribe, I don't care for this recent trend of perceiving something somebody said as some kind of abuse of "therapy speak" (before this comment I've seen a few stories about some actor "abusing therapy speak" and such lately, so I assume it's some new fad going on). I don't read about therapy, or had any therapy speak in mind. "Internalized" has been used for decades as a term, and here just means "accepted this lag as the baseline as they don't have a frame of reference". Might not even be the right word, I probably was looking for normalized (is that therapy speak too?). So there's that.
This describes so much software that I don't see how you can fault anyone for thinking it is normal.