How can people get away with this (Side note: In-Game mutes should apply in the Client too)

So, I played a game of Ranked last night where the first thing the top laner said in Champ Select was something like "If you hard int, I'm not even going to try. Sick of people inting and not letting a smurf carry. If you int, I'm just going to afk farm all game." He/she locks in Fiora, then insists we invade. When the invade goes sour and he/she and our support have to flash, he/she starts flaming, "Great players. I can see already," and proceeds ping that the support and mid laner are alive. I was playing jungle, and I ganked her lane, blowing their top laner's flash, but all Fiora could think about was question mark pinging me because of the route I took. I did well all game, but all he/she did was flame me. Eventually I got tired of it, and muted him/her and his/her pings. However, I was berated after the game in the post game lobby (AFTER WE WON), and it really got under my skin. I reported her, but still didn't feel satisfied, especially because of the barrage of shit that was flung at me in the PGL. Because of that, I got pissed that mutes in-game don't carry over to the client. Anyway, with these off my chest, it's time to get back out there.