It was soft, I'll give you that but you can't really complain about it being given. It was silly defending from Bailly - he's too keen to make challenges at the best of times but against a striker like Costa you've got to be even more careful. Costa's as streetwise as they come and he knows how to win fouls and Bailly fell into his trap.
You simply can't tackle if any contact is a foul. The ref has to decide if the contact was enough to merit a foul.
Honestly we are just playing rubbish today. Everyone is slow, no movement.