Demoted after one loss?

So after 5 failed promos to get into Silver 2 (mostly caused by those people who go like 2/9, but I had some bad games as well ngl) I FINALLY won my promos and got in... after a month. Win a couple matches then go on a nasty losing streak, drop to 0 lP, lose one game and get demoted. Seriously?

Here's the team I had to work with on that loss btw Q_Q. My score's not the best but not bad either compared to all 4 of these guys lol. How does one carry four feeders who take what you tell them into one ear and out the other? It's like trying to teach a chimp how to wipe it's ass. "It's just a game man relax" THEN PLEASE GO PLAY NORMALS.

Apologize if this comes off as a rant, my original question was why did I get demoted after only one loss?