As the title says, why can't they? Let the players decide if they want to play Respawn or SnD. Just look at my last three games the first two took nearly 30 minutes to complete, and in the last one, I was thrown into mid game when it was 4-4. Being a Respawn player, I hate playing SnD it bores me to death. I still remember the launching period of LP I use to get 3 back to back SnD like it's the gods choosen mode I had stop playing LP temporarily cause I wasn't enjoying and had switch regular rank HP/Control.
I love playing LP hope r/CallOfDutyMobile separate SnD from next season.