I seem to get worse players on my team during the first few games at a new rank

I've noticed that during the first 4 to 6 games in a new rank (EX gold 3 -> gold 2) I seem to get players on my team who aren't very good. The first few games in a new rank are always a struggle for me because even if I do well, I always get two or three people that just feed. As a jungle main, I'm used to having to carry players that are doing poorly, but it just seems like during these games, the average skill level of my teammates is decreased for some reason. I get players who don't even seem to understand some of the very basic things about the game. After the first few games, things balance out and I usually end up winning more than 50% of my games, but those first few games are always a struggle. I'm just wondering if that is purposely done by riot or if I'm just getting really unlucky over and over again. I started this thread because I just got demoted from gold 2 to gold 3 on the back of a 6 game loss streak. In the first game I got autofilled into support and did poorly, no surprise. The second game I did reasonably well and had a good impact on the game, but my top laner decided to die 14 times. Third game my team went down 0-6 early and 3 people just said "gg" and gave up, and the adc went afk in fountain. Both in the fourth and fifth games I did extremely well on graves, but in both games I had two people who fed their asses off. And in the sixth game my entire team fed. Before these 6 games, I climbed from gold 3 to gold 2 on a 5 win streak pretty much effortlessly. So I went from effortlessly breezing my way through gold 3 to getting dumped on 6 times in a row in gold 2, and I know that the skill difference between gold 3 and 2 is pretty much nonexistent, so my question is, who the hell is deciding who gets on my team?