Thank you and everyone else working on the Firefox browser and adjacent projects for your hard work. Don't let the noise of the internet lessen what you and the team have done and continue to do.
I'm sorry that happened. I wish there was some way to solve the "one jerk outweighs a thousand happy users" problem. I still vividly remember one guy being an asshole about my work on the Wine bug tracker a decade ago, regardless of how many happy users I know there were.
It's human nature, unfortunately. Reality television producers have known this for ages: the episodes that feature people who come off as irredeemable jerks always garner the highest ratings.