Skinny guys vs Huge guys in the weight room.

Now, I understand rep ranges and hypertrophy vs strength training, and all that. But there are some seriously huge dudes at my gym that move very little weight, and make tons of noise.
Then, there's skinny guys who move many plates and are quiet about it.

There's a couple guys in particular that do very, very little weight and treat it like cardio. This one guy was doing 45lb chest support rows for like 10 minutes, grunting and screaming the whole time. Mind you, he looked like someone that could roll that 45lb plate like a fruit-rollup.

I've seen these guys many times - they are always doing this. Which begs the question: Are they really achieving excellent hypertrophy results by lifting very little weight, or are they maybe achieving excellent results by lifting a needle?