Let me quote from reddit, March 6th AMA, Blizz_Daybringer:
Just to reiterate, how it came up.
- OP complains that in QM he was facing a premade, feeling it unfair.
- People respond that QM is not serious.
Now, either #2 isn’t a direct response to #1 (premade vs solo) or it also implicitly judges UD and TL as not serious due to #1 (premades happening). This argument was used in favor of HL before, actually.