Getting matched with players on your block list?

So I'm sitting in a Discord call with my friend and his roommate, and we're loading into a normal match. As I'm tabbed out, I hear my friend read the enemy ADC's name out loud, as it's a pun and he's probably amused. This would be great and all, except that the summoner name in question was that of a girl I went to school with. A girl who, after a year or two of her psychologically torturing me, convincing my (now ex-)friends that I'm the root of all evil and getting them to make a game of literally trying to get me to kill myself, and making mule account upon mule account on social media to stalk and harass me, I blocked on Leauge of Legends. Judging from what our mutuals have said, she also has me blocked.

I freak the fuck out and tell my friend I need to dodge. He realizes what's going on and consults his roommate, but by then, we've loaded in. So we play the game, I'm completely fucking out of it, the girl from school gets fed, and we lose. Cue the drama and shit talking and backstabbing and threats over three different Discord servers for the next fucking hour. Shit's still going now and someone just made an actual death threat over this nonsense.

I get that blocking could be abused in ranked, especially in higher elo, but is it _really _ that unreasonable for one to not want to end up in a game with someone they blocked? At least in norms? If someone is toxic—in real life or just in game—or feeding or has a history of AFKing or whatever, then of course people don't want to end up in a match with them. And if it's a mutal block, too, then clearly, it's not just someone blocking a player for being too good and not wanting to play against them. Is there really no way this could be fixed?