Originally Posted by Xavier227
some people are still going to abuse it
It's not pointless. The reason is that if you behave nicely in every game, you're going to get good reps, And vice versa. Now some people think it's pointless because "If I never flame, troll or trashtalk, people can still down rep me..." yes that's true, but only if you are standing on the fence; meaning you don't behave badly, but neither do you behave good. It's like you are silent all the game. No trashtalk, but no contribution either. If this is the case, you will be influenced by random bad reps.
However, if you make it a habit of talking nicely and helpful towards other players in every single game, you will be likelier to get more good reps, which in turn, will dissolve all the minor random bad reps. And I believe this is the point; to encourage every player to behave nicely.
Examples of good behaviors:
Admit defeat when lost. Smile and say "well played guys"
Buy wards, dusts and couriers for your team if you are playing support or you have excess gold.
Show humbleness when winning. No need for sarcasm and arrogance.