what is the point of blocking and reporting someone?

i seriously don't understand the point of blocking/reporting someone. i got stuck with two duo feeder noobs for 2 games. like wtf?! i know they were premade because they were speaking some foreign language nobody understood but those two butt pirates. one of the duos at least got some kills. he ended up going 7/15 and the other retard went 0/15. yes you read that right, zero kills and fifteen deaths!!!! i don't know why they were trolling. they just joined the game and immediately tower dove at lvl 1 before minions spawned. so anyways, the game was over and i said, well no biggie who cares. I'll just report/block those idiots. but little did i know my next game i joined they were in my same team!!!!!!! they ended up doing the same shit.

so what exactly is the point of blocking and reporting people if you are going to end up playing with the later in the future? my block list is endless. and grows with every game. anyone that feeds/trolls ends up in my block list and they also get reported. i've noticed that i've come accross some of the same players that previously trolls/fed. so wtf is the block option for? i know in other online games when you block someone, that prevents them from any future interaction with you. meaning, speaking, joining same game, trading (if it's and MMO), requesting to be added as a friend, etc.