Impossible For A Casual Player To Have Fun.

So, me and a couple of friends regularly play league and we have another group of friends who sometimes like to casually tag along. They're not the best but still enjoy to hang out and kinda play the game at a fun pace. Doing normal queues today 4 premade and 1 random, so everything was going pretty well pretty early. Our friend we invited who doesn't play often enjoys to just hang out top lane and what not and just chill and have fun(Wukong vs Garen). he didn't too hot but not to bad.

Things went downhill around 22 minutes in, our random 5th thought that top lane was trolling. Trying to defend him we explain all he did was lose lane, and not necessarily badly. He lost in k/d/a but overall was able to push the lane to their inhib. He had overall pretty good teamfight/communication with the rest of the team. By this point the random fifth had given up and decided to do his own thing, he basically pissed away the entire game when we were down by two. Every other lane had won and at one point we were up by 7 kills.

I ended up snapping a bit at the veigar(the 5th) I will admit. I reported the hell out of him(so did the rest of my teammates). I was extremely disappointed in the game and the experience I have had. Not just because of him giving up, he was wanting the entire enemy team to report someone who was barely level 30 and played league of legends at most of the time once every week. Threatening him that he was going to be banned, honestly... wtf is that?

So, what kind of player is league of legends ment for? That's overall what I am asking Casual/Tryhard/Both?