It might be a question of commitment signaling. Some reviewers might ding candidates that seem to have a ton of work going on outside of work. Maybe even more so if they see a candidate hasn't held a job > a certain # of years before.

Not sure if HR thinks that deeply during resume review, though. If you're not getting past that screen it's probably just match-the-buzzwords-listed-in-posting density—more "filler" words (started awesome website, did amazing things) means less % matching words