Competitive Attitude

I've been really confused this season as a type of attitude seems even more prevalent than it did in previous seasons.

It seems that teammates are ready and fully willing to troll each other at the drop of a hat. My question is simple... Why would you TRY to tilt one of your own teammates?

Examples: -People disliking the play of one teammate and instead of being helpful they decide to trash talk them the rest of the game. -People following around their devourer jungler and trying to steal camps from them. -Being capable of saving a teammate, but instead spamming laugh until they die and THEN engaging. -Requesting MIA pings from a teammate and either being told "watch your mini map" (likely in a much more negative way) or that player then spamming 6 pings off cooldown for the rest of the game. -People watching for mistakes so they can mock you in chat.

I simply do not understand attitudes like this (and there are many instances that I didn't mention). It's a team competitive game. Shouldn't the LAST thing you'd want to do be make one of your own teammates play worse?

Also, I understand there is an "Unsportsmanlike Conduct" report feature but, is it effective? Do people actually receive punishments for this type of behavior?

TL;DR - I feel like the majority of my losses this season have been because of teammates immediately adopting this "let's troll/trash our own team" attitude, most often before the 12min marker. I've made plenty of mistakes, but this mentality honestly seems to be the thing that ruins my games.