AQ is the worst hand they can have from our pov, along with QQ 33 and 44. That's not much of their ranges, and even against this part of their ranges, we're still not losing much money.

Calling the flop in this spot, it just puts us in potentially horrible turn spots. Like this one. Calling this turn all in is certainly more marginal than check/raising the flop all in. I think turn might be a fold, but I'm not sure about that. I'm sure that check/raising flop all in is printing money though. We might get JJ to fold and KJss to call, as one example.

We're never in bad shape on this flop, especially three handed vs fish.