ATP has 40 locations across the country with I don’t know how many instructors, so I have no doubt some are more cordial than others. While ATP does an excellent job training their instructors, guaranteeing a pleasant demeanor is a bit more challenging. As for the “just want the hours” let’s be honest, after you’re done with training why will you be instructing? Other than older retired pilots, I don’t know a single pilot who’s not instructing to build time, doesn’t make them bad at what they do.
I actually had a similar experience my first visit, but fortunately I was encouraged to try again and I was very happy I did. There have been people bashing (and praising) ATP on forums for years. Many washed out, many are sorry they paid 2-3 times as much for their training, and I’m sure a few have legitimate beefs. That said if after decades the worst they can come up with is an occasional rude CFI they met on a visit and the fact the instructors are there for the same reason they hope to be in 6 mos I’d say they’re doing pretty good.