Why the hell doesn't Riot fix the MM.

If I go and report someone, why in the everlasting fuck do I get put back in a game with them. I've reported someone 2 games in a row for being a toxic douche bag, and I've been lobbied with them FOUR (five, now) TIMES. If I go as far as to report AND block someone, why do I get paired back up with them? Is the point to just piss me off so you can ban my account? I really don't get WHY you put me back in lobbies with people who are PURPOSEFULLY trying to agitate people. When my game is lagging I get on edge. Since the last patch, I've been lagging like someone who just got the internet. Now, I'm put back in the same game with the person who thinks that me losing in the Poro King is trolling? Seriously, get it together Riot. If someone reports and, let me emphasize this, ////BLOCKS//// someone, don't put them in the same game together. It puts people on tilt and ends up with more accounts banned than should be.