Genuinely confused about people throwing games to derank.

Yesterday I jumped into a competitive game. Before the ban phase started, most of my team pre-selected which heroes they wanted to play, including me. I pre-selected Invisible Woman, and another player pre-selected Spider-Man.

The ban phase starts, and I start pinging potential heroes to be banned (none who were pre-selected of course), only to see that two people immediately lock in Spider-Man to be banned. I thought it was weird, because someone already pre-selected him, but I shrugged it off thinking they probably just didn't want to deal with/have a Spider-Man. The rest of the team tried to ban other heroes, but unfortunately the ban went to Spider-Man.

The next ban round begins, and the same two people immediately bans Invisible Woman. By now I'm like, what the hell is happening? I typed in the chat asking what they are trying to do, and that's when it all started. They started saying things like they are EOMM agents, and they are here to give a free win to the enemy, blah blah blah.

Once the match started, they just ran and fed the enemy team, without doing anything in return. The rest of our team tried for a bit, but it became obvious after a minute or two that it's just not going to work with two people throwing, and basically just had to wait out the timer.

By now we were all fed-up, and since we just had to wait it out, I asked them what was even the point of them throwing like that, and how their accounts aren't banned. They replied by saying that they are trying to derank, and that they allegedly got the accounts the day before.

Eventually, the match ends and we lose, and our team asks the enemy team to report those two players. I wait a bit before queuing again. Once I get into the new game, I just see a message from the enemy team "I am an EOMM agent, giving the enemy a free win." I think to myself, this can't be the same people (their names were hidden at the start, so I couldn't see it until the match started).

The match starts, and everything feels like a normal competitive match. I didn't think to check any names of the enemy members at that point, because I could always see all the enemy team members during the fights, and it didn't seem like anyone was deliberately throwing. The enemy was pushing hard (convoy) and even made it to near the end.

But that's when they started typing in the chat again, saying how they are now going to give the enemy (us) a free win, and the enemy team joining in the chat to ask us to report this person. Once the second round started and we had to push the payload, the difference was just so big. I looked at the names of the enemy team and noticed one of the names of the people who threw in my previous match. The enemy tried hard, but with one person throwing like that, they didn't stand a chance to win. Probably should have just given the enemy the win, but that just enables the person to throw more.

I reported the person again, and I'm hoping the rest of the group did too. I just don't understand why they are doing this, and what the point is to derank? Why don't they just play Quick Play, and how are they allowed to keep getting new accounts?