Well, the notion of "normal" - kept/keeps changing with every generation. This days, normality is defined by the largest groups of people within a society (back in the old days used be defined by the elders and the king of a nation - or the chief or a tribe). Tho, if there's a large enough group of people who identifies with a certain lifestyle - it really doesn't matter what the majority considers normal - cause you have "your own people" within a society. To name a few: Rockers, Vegans, Atheists, Gamers, bodybuilders and so on... Most of this cultures didn't exist in the past - or even worst in some places you'd get killed if you'd identify with atheists. As for gaming, more exactly - online gaming... this culture was actually expanded to this point and "normalized" - by people who are now in their 30s. There was no such thing as online gaming in the 80's and prior to that. Also, the technological evolution of PC hardware - would have never advanced so far - if there wasn't such a large group of people who liked computers games - and thus, they invested in better and better hardware to play their favorite titles.
That beings said - depends who you're asking. There's lots of people who don't like computer games - and obviously, those will say it's not normal. As for younger generations - well, almost the same as older generations (especially if it's the community of a competitive game like LoL) - you're bound to encounter quite a lot players who happen to be disrespectful and toxic. Younger generation trying to insult the older players by calling them "grandpa" - while older generations insulting the younger ones by calling them "kids". Shit like this comes with the territory - so don't don't fret about it. 🙂