Everyone and their mother knows that Corey has a weak chin. Something can't be "exposed" if it's already widely known and brought up at the first opportunity.
But by that logic, you should have bet the hell out of Glover Teixeira, Ilir Latifi, and Johnny Walker against Corey Anderson as favorites, ALL much bigger punchers and more dangerous strikers than Blachowicz...and you would have lost every single time.
There are bets that miss which were are dumb, ones that miss which are okay, and others which are good.
Similarly, there are bets that cash which are dumb, okay, and good, too.
That's why looking at the final result alone isn't nearly enough, and simply saying "my bet cashed, therefore I'm right!" or "my bet missed, therefore I'm wrong!" is an absolutely horrible way to approach gambling.