It's a different kind of wrong as string-betting; string betting is an attempt at making an ambiguous action. Is it a call or is it a raise? Hah, clever me, I get to choose what it is after tricking you into thinking it's just a call. That's an obvious violation of the fundamentals of poker, namely that the action so far should be clear and unambiguous to every player.
There's nothing ambiguous about saying "wow, that's a big pot" - it's no kind of action, and cannot in any circumstance be reasonably interpreted as an action.
I think you're simply begging the question here. What makes it poor sportsmanship? The psychological aspect? Can't be that, that's accepted as fair play during heads-up. How is it angle-shooting? Literal angle-shooting is looking at someone's cards surreptitiously, which is obviously against the fundamentals of poker. Figurative angle-shooting is likewise an attempt to circumvent the rules... Naturally, if the rules adopted by a casino or tournament or home game say "you must act, physically and verbally, as if the game does not exist when the action is not on you" then yes it's angle-shooting, but as I said that's just begging the question.
I think there's a pretty significant difference between those two. The first is from a player with a live hand; the second is from a player with no involvement in the hand (any more). I think it's quite reasonable to restrict participation in a hand to those who are in fact still participating in the hand. So, no, I don't think those are the same.
I think this could be your strongest argument, but I'm not persuaded. If I'm saying something in an attempt to get other players at the table to misplay their hands to my benefit, how can it be said that I'm playing their hands with them?