This response is part of the problem.
People feel uncomfortable about others who look really crazy/shady for public transit or in parks, and in response they're told, "have you considered that maybe you're just overthinking it?"
Instead of fixing the problem, we blame those who have the audacity to notice.
Both things can be true. People can have exaggerated fears about the dangers of transit (especially compared to driving, which people seem to pretend is relatively risk-free), and the crazy / shady folks on transit can still be a problem and still need to be addressed.
I can only speak from my own experience riding transit in Seattle for 9 years. I've never had any issues. Sure, there are sketchy characters, but I've never been bothered, and never had anyone bother me. I definitely see news stories about bad shit happening on transit, but when you look at the number of people riding transit vs the amount of bad things that happen, and you look at the number of people driving and how many people die or get seriously injured in the city daily from car-related accidents, it's a no brainer. You don't see people dying on transit every day, but car-related fatalities are a daily occurrence.