First you mean "newbs like me" when referring to yourself as inexperienced. A newb is NEW at something, like "Hey newbie, ready to learn how to last hit in League today?" A noob (this is an insult btw), is someone who thinks they know everything, but really doesnt know much at all. They say/do dumb things all the time like if you just wiped the enemy team outside the base and theyre all on 40 second death timers, instead of pushing with the minion wave into the base for the win they run for Baron... and think youre stupid for not doing it too. They say/do those things cause they really dont understand the game, but act like they the grand king of tactics and strategy.
While were at it, the final thing is a nub, aka. a "Non Useful Body." These people take up space, they blocked a real player from getting into a match. Troll picks in this game, people who type rage novels in the chat instead of playing are nubs, cause they arent useful, but they are a body in the game.
So there you have it, newb, noob, nub. Three different words, different meanings, misunderstood by a generation of gamers because words r hard.
To your point of your thread here. Many people are just leveling alternate accounts. Maybe they want an account where they play ranked as Mid/Top, but dont want to lose matches playing on their Bot/Jg account.
Others can only get an erection if they cause misery and pain to others, and need to play against people with less skill than themselves to feel good about themselves. Theyre bullies, that one dumb as hell kid that has been held back 3 grades and is bigger than the other kids, and picks on them. I know theyre frustrating to deal with, but honestly imagine how hard their actual life is if playing video games against people of lower skill levels to win is how they have to feel good. Its really sad. Also, theyre the real noobs, they think theyre dominating, when theyre really just picking on newbs.