There is a big difference between actors and athletes. Most actors, those who open their pieholes about politics being the major exception, just act. They play a character. You watch the show and enjoy the character. Off stage they might be a drunk, a scientoligist, a cross-dresser, a Canadian, whatever. It really has nothing to do with what they do for a living. As long as they don't tell me who to vote for or what brand of corn flakes to buy, I could not care less about what they do off work time.
The modern athletes, expecially ones in individual sports, make their real money from endorcements. To his credit, Woods has rightly avoided politics, but he is featured daily telling people to buy Nike s**t, Buick crapmobiles, AT&T, etc, etc, etc. He puts his reputation on the line, and he thus if I, the customer who is always right, want to avoid Nike et al because of Woods, then that is my business. Further, if I am smart enough, and I and pretty much everybody with one exception, am that smart, to see that everything Woods has done since he got caught by his wife is a scripted skit and act, that is my business.