So being a respected mob boss instantly equates to fantastic fighting prowess? Does that mean US presidents are all a bunch of Rambos, or that Marlon Brando's character in the Godfather movies could fight a Predator mano a mano?
Look, no human can be a threat to a Predator. It doesn't matter if it's Dutch or the Godfather, they can't hurt him unless the Predator deliberately makes himself weaker to have more fun.
Yes, I can see the Predator having fun in killing the Godfather, and even the president of the US, which would be impressive to get his skull after going through insane levels of security to get to him. Though that would imply the Predator is aware of political surroundings, which sounds too boring for a Predator to deal with.
It's not about finding a match to fight with one on one, no human can pose a threat like that. It's about finding a trophy that means something, like a well trained soldier, mob boss, etc. People who pose a threat to others, who are considered dangerous, that's a good hunt for the Predator.