Of course it tarnished his reputation. I've seen people using this multiple times against him. But he has the (bad) excuse of not dealing with his money personally.
But the club is a bigger institution. The Neymar affair is a mess, a really bad one. They've been doing bad deals one after the other. You keep saying "Letting Abidal go was correct decision", but they didn't replace abidal. 4 years without proper reinforcements. Not to keep being the best team ever, but to avoid shaming like the 7-0 against bayern. I really don't get why you feel you have to defend these guys.
He is one of them