>>10129015Because Callis admires the viciousness and the meanstreak of the BCC, something that he has found lacking in Kenny lately.
Callis has, for months, been telling Kenny he needs to stop being a fun tag guy, lose his friends, lose his distractions, and regain his killer instinct.
Everybody saw Callis betraying Kenny from a mile away. It's the Moxley part that's the surprise, you're right, but it makes sense and I think that Don decided to go this route after he got busted opening falling onto that studio light, kek.