Wrong. The npc's weapons and armor are in poor to moderate condition, most of them dont use the most powerful ammo types and none of them have as many perks as you do if at all, so playing on very hard compensates for it. Ulysses has 2 perks - Finesse and Toughness and if you have one of the level 50 perks, his Finesse perk cant affect you at all. I can kill Ulysses with 2-3 shots on normal. This CANNOT be as powerful as the devs intended him to be.
Considering that he's, as far as we know, a mostly normal human... yes. It probably is. He's not a power armored goon or super mutant, a freakish mutant fused to tech, or some ludicrously tough tribal nutjob in heavy metal armor. He's a glorified scout wearing an old duster.
And what the heck are you hitting him with that's killing him in 2-3 shots? Man has around a thousand hit points, for crying out loud!