I don't really see where the confusion is. Far be it for me to speak for Sprint's marketing department, but Paynefanbro's explanation, while succinct, seems perfectly plausible. From the link that you provided it doesn't seem that they're keep a public count of cities (or communities) so I'm not really even sure what the issue is here.
What I'm confused about is that this was your original gripe:
You asked to be corrected if you were wrong and indeed it was shown that you were. It would seem that in light of that you would make a correction, retraction, mea culpa, anything here, DSLR, HoFo, Twitter and wherever else, but instead you appear to be moving the goalposts in order to quibble about semantics. That looks really bad imo.