@Riot unsportsmanlike behavior not on the report list?

so i just got out of a game and reported the graves on the enemy team because he was gloating about how his team was winning and saying things after he died like "lol only using one hand" "do you guys even realize that you aren't worth a flash?" or "this game is so easy lol" this to me is strait up unsportsmanlike behavior but that wasn't an option to report for so i had to settle with negative behavior. this is really upsetting to me because after the game i had a conversation with him about how that isn't cool but his reply was that it won him the game and made my team angry and prevented us from making good dissensions. and i have heard this excuse used many times for poor behavior and it concerns me that it seems like riot isn't trying to bring down the ban hammer on people doing these kinds of things, even though they are trying to be the most sportsmanlike video game out there. and i tried saying to him that games (i think) should be won by skill not how good you can down talk the other team and what makes a good game is when both teams are playing at there best and its a constant back and forth match were one team finally pulls out on top regardless of if its your our theirs and not the enemy's nexus exploding. but all he did was point out that he won. and what really upsets me about all this, is i see it in the pro seen as well ill see teams trash talk one another and show horrible sportsmanship just to try and throw the other team off there game. Dyrus i remember on stage in front of millions of people called all the teams in NA except for cloud nine non-existent especially CLG. https://www.youtube.com/watch?v=FYI0Tf7-Vvo another example is OMG after a defeat, they wont shake the other teams hands. these people are role models for the whole community, and if they aren't showing sportsmanlike behavior just so they can win a game, then why should anyone else?