SamHB, you're free to deny obvious bias against outspoken Christian athletes. But be aware that determined denials ultimately lose credibility.

Do you even deny that Tim Tebow was criticized more harshly, and more unfairly, than other quarterbacks? If you take your denial to that level, the loss in credibility will be complete. If, however, you admit that liberals criticized Tebow more harshly than others, then why do you deny it with respect to Gabby Douglas? Notice that you never provide an alternative plausible explanation for the unfair criticism of Douglas.

You say that liberals do not criticize their Christianity specifically, but it obvious why they criticize other things instead. If any liberal criticized someone directly for being a Christian, then the liberal would lose support. Liberals are not that dumb.