That's debatable imho. We simply don't know how strong Boa really is. She has a completely broken DF and CoC though, so we can guess that she might be really strong.
What was bothering me more was simply the completely baseless Coby hype. This dude is two years removed from being absolute one-shot fodder to pre-skip Luffy and still hasn't shown anything impressive to even put him in pre-skip Blueno category. He managed to eliminate a rocket, wow, what a biggie. Literally all low tier fighters in OP can do that.
To even mention him in the same sentence as "captures Hancock", "Lucci level" or "might be YC level" is sheer stupidity.