SBMM and MMR are lies

"Next time someone at Respawn claims there's SBMM or MMR know it's a complete lie. Feel free to rub this in their face.
If there actually is MMR or SBMM the system doesn't work, whatsoever, so it might as well not be in the game."

They have said there is a SKILLED BASED MATCHMAKING, which manipulate the matchmaking based on the variable skill. But to my knowledge, they NEVER said that that this SBMM in casual tried to match equally skilled player against each other... Thats the thing you are missing..  They even explicitly describe ranked with the text "play against equally skilled players" or something like that, but this text disappears when you select casual mode.. 

In my experience, this SBMM tries to make "even" matches, rather than matching equally skilled players against each other. So for example; if there are 5 empty lobby slots on the servers available and there are 20 master-to-pred skilled players queuing at the same time, the matchmaking rather spread those 20 players so each lobby has max 4 of those players, rather than let one of those lobbies have 20 etc etc.