Journalists misuse that word and plenty of others all the time. A writer from a football blog is hardly a reference standard for word usage.
Look, one team is going to win the SuperBowl. Not two teams. We all know that when those two teams enter the stadium, every person on the planet is going to have their favorite team. Nobody says "I don't know. I kinda like them both". Nobody wears a jersey from one team and a hat from the opposing team at the same time unless they just don't give a shit what happens in the game.
You've gotten the word favorite confused with "Top 2 choices", Top 3 choices", etc. You can have multiple ice cream flavors that you like, but the word favorite means the one you prefer above all the others. So if you have multiple flavors you like equally, that just means you can't make a decision as to which one is your favorite, which is a completely different issue altogether.