Strongmen are VERY strong but a Strongman and a Navy Seal usually and generally have different skillsets.
While one is specialized in lifting as much weight as possible, the other specializes in incapacitating/destroying other people.
Of course, there are many factors, the difference in size, strength, speed.
But in general, the Navy Seal have a better skillset for this kind of event (incapacitating a person).
I assume the Seal would be somewhat faster than the Strongman, and would attack his groin,windpipe and whatnot before the Strongman could lift him up and perform militarypresses with him.
There are always exceptions though, in one situation out of 10, we might have a very athletic strongman which moves faster than general and knows some fightingskills, while this Seal in question may be sloppier than normal, which would result in a victory for the Strongman.
But generally, i'd put my money on the Seals over The Strongmen.
Now, Ninjas VS Pirates, that's another question.