Janitor is right about the biased way size is considered & presented. However, mistaken that an average height man cannot be 240 without being fat. Tua was 5' 10" & 243 vs. Lewis, over his weight but not fat. Usually they are fat at these measurements, but with enough muscle need not be. Granted though that without PEDs, they are gonna be at least a bit overweight. Although with PEDs, you have guys who are under 6', right around 300 lbs...With minimal body fat. Gazliion X Mr. Olympia Ronnie Coleman was a fairly early example. Not that this is good for boxing, just saying it happens. Is Takam (6' 1.5") really "shredded" at 240 though? Not just not fat, but very low body fat? He has abs-but some folks have definition there even when overweight. At a 40" waist I still show a faint asymmetrical 4 pack, & always did even when i weighed more. Genetics & maybe endless sit ups when a thin kid mean sometimes subcutaneous vs. visceral fat distribution can allow midsection definition even when someone is not otherwise lean or "cut".
Look, I am sure that theyre have been 5' 10'' bodybuilders, who were in shape at 240lbs. However it is not a viable model for a boxer of 5' 10'', especially not is they are giving up a lot of height and reach.
That is something different than you said before. Another guy corrected you on details in the past. There have been bodybuilders with very low body fat at near that height at ~ 300 lbs. Janitor! Although PEDs in lArge part got them there. You do not have an understanding of these things... But as for 5'10" & 240 lbs. as a boxer & NOT overweight...It would be extreme & challenging to be a top boxer at this size, yes. Although not generally ideal, again Tua was 243 vs. Lewis, & was good enough to deserve that title shot! So it can be done.
I think it would be both gracious and prudent if you qualified your original remark with ,"generally speaking".
Generally speaking, I don't think that I would advise most men of 6' 5'' to come in very far north of 245.