Earlier quoted context omitted.
Then I'm baffled. There seems to be a recent trend where non controversial things: - the documentation and character support issues can be 'bugs' - defaults that fit most users are good - reminding someone being personal of the HN guidelines ...get moderated up, then down to -3 or -4, then back up to 1 again.
I think it's that your response sounded like a lazy dismissal. Reasonable defaults are good, yes. That's pretty uncontroversial. But nobody has established that Firefox's behavior is less reasonable than the alternative — for example, the comment you were replying to noted that both approaches have their fans — so your out-of-hand rejection on behalf of "users-on-street" sounded imperious.
Noticing the folk in the conversation there's lots of newish accounts, and some are replying before they've actually read what they're replying to. Downmods for 'I disagree' are more popular now as well.