I think what brad is trying to say is that it’s like the words strongest person. Lets just say this man weighed 350 lbs, but he can bench press and lift 500-600 lbs.
No matter how hard he tries, he can’t lift himself up off the ground. He can lift way more than his weight, but it literally wouldn’t matter if he could lift 1,000,000 lbs. he cannot lift himself up, because he cannot exert a net force on himself.
Same thing with SSTF. It all comes out of the same body, no matter what you call it.