People so used to being able to say outrageous things on the internet with no consequences + people watching so much violence on tv and the movies that it is normalized + the occasional psychoactive substance for some people = they start acting that way in real life.
Unfortunate but predictable.
Sorry about your encounter with shirtless skater guy; yours is likely not the only day he has ruined recently. I wish his type was less common than it is, but I've been wishing that for several years now and it doesn't seem to help.
Hang in there.