Idk if he’s my goat, but I feel like Monzon doesn’t get the attention he deserves in these conversations. He was a scary dude.
He is "better" at boxing though, it can be reasonably argued. I understand what you're saying but it really depends what you mean by "better". I would certainly say Gassiev is the more effective boxer but "better" is hard to define and up for debate. E.g Do you have a "better" diet than me because you eat more calories? Does that make you better at eating?
Gassiev is better than Loma because he easily beats him in the ring. Loma needs a much higher weight handicap. Loma is better p4p. Gassiev is literally better.
For years I always thought it was Robinson. But after reading up on Harry Greb over the past few years, it could well be him. Like you've noted, he gave away height, reach and weight, and he'd never have been cleared to fight today due to his eyesight. So his resume is truly remarkable. But from reading up on his style, I think Robinson was definitely better technically. I guess it defends on your criteria.
They stand alongside their fellow greats, not above them. Not unless you're just rating on a H2H basis. But even then, Floyd wasn't unbeatable.
Floyd was obviously past his prime at WW. For most of his time there, he was a safety first fighter with bad hands, who was happy to potshot and outspeed inferior fighters. The guys below would all have had a great chance at beating him at WW: (Hearns would have been an absolute certainty, as Floyd couldn't have outboxed him, and he didn't possess the power to have outfought him) Benitez SRL Hearns Duran
It's not absurd. It's just how you word things and how you interpret them. The greatest should be who you think was the best fighter, taking into account all of the relevant factors.