That could explain the difference between rr and Firefox, but it doesn't explain the difference between rr and all the other developer-oriented projects with toxicity issues.
There's variance in developer experience and skill as well. The software's purpose functions as an audience filter. There are still probably toxic people out there using your software, but not as many so they're less likely to bother you.
From what I've read about rr, it sounds like awesome black magic, and I'd imagine most users appreciate how difficult its task is.
