That's a great question, made all the more significant with characters like Colin Kapernick. I'll take a stab at it.
Tim Tebow is that rare person who is so thankful for God's love and forgiveness, that he is unashamed to show it, no matter the venue, no matter the occasion. He has always done so with class and dignity (compare for example, the rediculous end zone antics we have watched over the past 10-15 years).
Tim Tebow is a Christian, and he is not ashamed to show it. In a politically correct culture, (yes, even conservatives are often caught up in it), Tim Tebow has deflected attention from himself to the God he serves. In so doing, he is wrongly accused of drawing attention to himself.
But I'm not surprised by any of this. His Lord is Jesus Christ and Jesus said, "If the world hates me, surely it will hate you."
Tim Tebow takes another command of God seriously, "If you deny me (God the Son) before men, I will deny you before the Father." Would that we had another thousand Tim Tebow's in professional sports, and elsewhere. Ironically, the more he is mocked and ridiculed, the more he fulfills his purpose.
I wish that we had another ten thousand Tim Tebow’s in local, state and federal government.