Often these sorts of inconsistent decision making occur because multiple people making decisions disagree. Maybe some person high up in HR in change of recruiting scheduling decided Duke and A&T would be visited on these days. Maybe the person in charge of planning the details felt very strongly they were better off putting whatever resources earmarked for A&T toward events with minority-focused engineering student groups at Duke, and so raided the budget without going head-to-head with the person in charge of recruiting scheduling.

Which is what most probably was the case. Resources are limited, so why waste them.

Besides, I do not really get why those dog&pony shows still exist in the first place.

For the same reason you don't serve leftovers on a first date with someone you're trying to impress. Which was ostensibly what this firm was trying to do at A&T.

> Why bother going to NC A&T if you didn't want the students from there? It's performative at best.

You may have answered the question yourself. This is just a guess, but perhaps some employers see business value in those performances.

Better half-assing it than not going at all, right?

I'm of the opinion it's better that they go, but reasonable people disagree. There are certainly potential economic benefits to the students at A&T at the time, but it could be argued that longer-term cultural progress is hindered by such token displays.