You think Barca agreed to him playing against them or are the rules in Europe different so they had no say in the matter?
Perhaps if Bayern are paying his wages, which I suspect they would be doing to secure that type of loan, part of the deal was he can play in all competitions.
Clearly Coutinho has no loyalty to anyone let alone Barcelona I think the ref allowed it just for the bantz It's not like this is a real Champions League anyway
Did your match report not mention the fact he didn't really celebrate either of the goals or the assist? He just doesn't fit in with Messi's click but he is happy with the club.
It's a small club mentality mate, usually when players move on from a big club you say "ok, who's next." When it's Liverpool they panic cos they are in fact a skinflint midtable club posing as a top one and when their players leave they say "****, when will ever have one as good as him?? "