Serious question: do residency programs provide alcohol just to bring out the true colors of the applicants? And do residents hedge bets on which dumba$$ applicant is gonna get drunk and make a fool of himself?
Absolutely not. The purpose of in-person pre-interview meet and greets is for the applicants to get to meet the residents and get the vibe of the program - it's not a "trap" or "test" in any way. It's supposed to be a fun social gathering. No one's going to care if you drink one drink too many and share something embarrassing or whatever - this is a gathering of friends, and almost universally, the residents generally outdrink the applicants anyway. Besides, of the few people I've seen put their feet in their mouth during one of these, almost all were completely sober.
Does this actually happen? Because I find it hard to believe MS4s on the interview trail are socially inept
Absolutely. Think about it - in what situation could a socially-inept, sheltered young adult better thrive than medical school? A college student with zero social skills but a 4.0 GPA and a 95th percentile MCAT is still getting into medical school and probably at least surviving clinicals. It's certainly rare, but I see it every year. In addition to the example you quoted (which I personally witnessed), here are a few more:
-During pre-interview zoom introductions, one applicant made a racially-insensitive joke about another applicant, which every single applicant and resident heard.
-During zoom interviews, one applicant had a TV program on, unmuted, on another monitor that was partially visible from the zoom camera, and was clearly half-watching it while being interviewed.
-In-person pre-interview: one applicant asked many questions about the program and city, and then negatively compared the program/city to other places at which they'd been offered interviews. They then asked other applicants where they got interviews and said things like "oh, I'd never even apply there. Really? I feel like (program X) is kind of beneath me". About half the residents/applicants heard this.
-During interviews, one applicant discussed their ideas for race-based care which were based in the presumption that members of certain ethnic groups are significantly less intelligent than those of others.
--During interviews, another applicant discussed their idea for dealing with healthcare-related violence, which was having hospitals provide firearms and training to physicians, presumptively so that they could shoot violent patients.
These weren't all at my institution, but almost all of them were at T20 program interviews.