why do i fight 4 diamonds in flex #2

again, fighting diamonds all over the enemy team when i queue up with a silver this is ridiculous i understand they are separate mmrs but if you are diamond in solo/duo, but gold in flex YOU SHOULD NOT BE FIGHTING SOLO/DUO SILVERS, even if youre both gold in flex every time i get to my series i just fight full teams of people that are diamond in solo/duo but gold in flex NOT to say mmr should be shared, but there should be restrictions in place so that im fighting people my rank or at least within my division or at least someone with 2 divisions of me. No reason a silver should be matched up against diamonds in a ranked setting its terrible for both sides as it allows people already high up climb easily but those that are below are trapped. Improve your matchmaking PLEASE!