Because riot doesn't
1)give LP to who deserves them
2)doesn't provide players with tools needed to carry trolls
Basically in bronze, every player is a troll whether they want it or not.
-If you're top, you can be sure jungler will come inting your lane and the ennemy jungler. Bot will also feed.
-If you're jungler, they will ALWAYS make sure to die just before you gank. You will ping, you will tell them to play safe, but they won't. They will never follow, because they're too happy that someone keeps their laner busy so they can kill a few minions (at last!) Of course, the ennemy jungler will be 10/0, always camping you when you try to farm.
-If you're mid, you can be sure you'll get perma camped 1v2, v3, v4.... While your jungler is afk and other lanes feed hard.
-If you're adc, your support will suicide under tower at lvl1 and blame you for being noob. You will control lane like a god, pushing and pulling at the perfect moment, so the jungler only has to walk on lane to get a double kill. Buuuut.... He won't. Because you pinged "help" and he's offended you might dare to suggest anything to this great strategic mind. Of course the ennemy jungler will be 10/0 and gank every single time your lane pushes.
-If you're support, pretty much the same above except your adc can't last hit, will never try to poke and will watch you die for the same reason they don't follow : "omg I can hit minions safely for a few seconds"
Of course, the ennemies are easy. You outplay them without effort, you dodge everything they throw at you. But what is the point when that 25/0 rengar only has to press R to one shoot you from the other side of the map?
Of course, you predict their every move, you know exactly what to do. But what is the point knowing they're gonna baron, even before they even thought about it, when team score is 50-5? Yes, you would win the game if all your team simply right clicked bot... Except that blue buff was so appealing to them, they all gathered there. Yes, all 4 of them.
The problem isn't that ennemies are better than you, it's not that you don't have enough knowledge of the game... It's the guys you're playing with are unpredictable.
The only way to get out of bronze, is to think like a bronze. To take absurd decisions, to expect irrational outcomes. Basically, to DUMB DOWN.
Which is, literally, a stupid thing.