I see you're not very familiar with Toronto sports fans.
I'm glad the Jays were able to get such amazing value for him, so I don't see why there'd be any reason to be bitter, but I guarantee you that the boos will be thundering the first series Lawrie plays in Toronto. That's just what Jays fans do. It doesn't matter on what terms the player leaves, there's always remarkable bitterness for no apparent reason towards pretty much every former Jay. I went to one of Vernon Wells' first games back as an Angel; the "VERRRRRR-NON" chants were deafening, and he'd just committed the unpardonable sin of signing a huge contract and being traded away (and he wasn't even very good for the Angels, so it's not like people were made he'd turned it around).