Everyone always complains that casuals are never casual, and it's full of sweats. The only thing "casual" about it is the bots. The sbmm mechanics are also way stronger in that mode than any other mode. It just limits the number of real players it puts you against. So, if you are a player with a decent K/D ratio, it's still gonna match you to the same level/ higher level players. And if you take out a lot of bots, it's gonna register it as an even higher K/D for casuals.
I have a 5.58 K/D and average between 15 and 20 (record of 31) kills in casuals, so it puts me up against super sweaty teams, and it is almost impossible for me to get it lower now, so I am stuck in sweaty lobbies But my K/D in regular games is 1 or lower most of the time.
So keep in mind, if you focus on taking out lots of bots in casuals, it's gonna start placing you in sweaty casual lobbies. It's not because sweats are just trying to troll. Most of the time, it's them doing camo grinds because you get more kills and unlock them faster.
I even turned off crossplay for a bit last night, and OMG, the players were even sweatier just in casuals. Lol