@Anon/Alex; all of that is fair and, realistically, I wouldn't mention that in a letter and was mostly venting.
That said... I think a lack of congeniality may be too generous but the words I would use are probably too harsh. To me, it was more that there was not even any form of apology or anything of that sort. I agree that it was a small oversight but I think it was handled poorly further.
To me, it's mostly disconcerting (and has been colored by) Georgetown doing some other kind of weird stuff like seemingly (and willingly) negging their waitlisted candidates. That's sort of what's coloring my perception of the misstep. I would also say that administration and support staff (i.e. career services) are quite important for a law school and is relevant but it's a hard thing to ferret out and all are likely similar. I understand it's different groups, but that with the combination of the other sketchy admitting stuff is, IMO, a bad indication of how much they care about students. Again, I understand the gaps in what I'm saying, but it's shifted my default of trusting that they are supportive of students to being uncertain.
Finally, what Alex said is 100% right. Ultimately, I'm in at a better school than Georgetown with significant money and a low COL. I don't know that I'd consider Georgetown for less than $30,000 over my Duke offer (I haven't crunched the numbers to know exactly but it'd definitely be in the five figures), and I don't see that happening. Living in DC doesn't have a value to me.