Match Making has become horrid.

I don't understand the league of legends matchmaking at all. In normal's I get paired with bronze/silvers the majority of the time when my MMR is around 1900 It doesn't make any sense. In ranked I saw a plat 1 adc duoing with a gold 4 mid So i though't surely the enemy team should have a gold player to even it out? Wrong the gold 4 ending up laneing against a d5 mid laner and fed so hard. Our gold player wasn't a smurf either he had a 49% win rate in gold 4 in 500 games, the plat 1 ADC on our team was boosting him. This isn't a one time thing either its quite consistent.

Aside from ranked I still don't understand how normal mmr is calculated. I'm currently a plat 3 player so why am i playing with and against bronze/silver players? I thought to myself maybe its because i play with my friends a lot in normals who tend to be around that elo but I'm not sure. I've honestly just grown sick of it. I stopped trying to play and make calls because when ever I ping a silver bronze player and tell them to get the turret or objective etc.. They end up flaming and I've even had people mute me saying I'm toxic lol when all i did was make a call. I'm just going to troll in my games I'm sick of playing with players 2 ranks below me. Its not fun and i don't enjoy it.