As another person who mostly reads here, a good question is why is it so hard to see attitude and performance linked?
I don't manage pro ball players, but I do manage computer programmers, and in that field it is impossible to separate attitude and performance. I don't see how players would be different.
Someone needs to improve, you let them know that, they get an attitude with you rather than working at what they need to improve on. Pretty basic stuff, and sure isn't limited to ball players. In a nutshell that's what was said about Willy. The only real punitive option was to sit him, so they did that. Time served, he's back on the field.
Why is that so hard to understand?