I'd agree if the upper bound of unmetered and uncapped bandwidth were so far in excess of the possible upper bound for this application that it were silly to consider - but, like I addressed in my comment, it's very much not.

If he were only talking about meters or caps, then that would therefore make his point a bit of a non sequitur in the context of an argument about whether tarpitting/blackholing a connection is risky for the serving party.

(FWIW, at past companies I've not-infrequently encountered network saturation even without an artificial cap from whomever we were peering with.)