I don’t think that’s what the meme is claiming.
I think instead it’s just claiming that all fossils have the same implied increase in maximum size implied by the paper, not just T rex.
I’m guessing the illiterate paleo fans were excited that maybe T rex was king of the dinosaurs again, but the logic fails if all the dinosaurs get bigger max sizes…
That does make sense, though I read it as:
[the new, expanded] upper body size limits…
Is how I read it, but your interpretation works well too, so I don’t really know now.