This is exactly my reaction. Seeing players earning big money really upsets some people, whereas seeing the owners, or the CEOs of failing companies, etc., doing so does not cause nearly such a reaction.
Such salaries for players are portrayed by these folks as "undeserved." I guess seeing players make out well causes even dyed-in-the-wool conservatives to forget completely their commitment to the free market. Why do the top players earn multi-million of dollars during the (often brief) years they can play? Because the top players bring in more than enough money in turn to make substantial profits for the owners. Because they are worth it in a simple economic sense! People pay to see them. That's the American way, right? You can't be earning too much if that is what you are worth in a competitive market to the organization paying you!
Even more so - why would anyone earning a substantial of money upset others? Especially people who did not come from a life of privilege and family wealth. Good for them! And no skin off my teeth, unless it results in me being priced out of tickets. Is that the problem? Frankly I doubt ticket prices would drop much if we undercut play salaries. And aren't most of us watching on TV? So is it jealousy or a feeling that the common people (perhaps certain common people in particular) need to be "kept in their places?" I wonder...