I think Kyrie's issues with the night out that evening was that is in the middle of a home-and-road back-to-back which coincided with a start of a 3 game road trip. And Kyrie asked the younger players not to go out, and they did anyway.
While the incident itself is probably not that big of a deal in isolation, it's interesting to look at the box score from that game and see that Tatum, Brown, and Rozier shot a combined 6-24. To be fair, Horford had a bad game as well. But the C's then lost two more roadies against supposedly inferior opponents in Orlando and Brooklyn to close out the trip 0-3, and so it's understandable why Kyrie may have been frustrated.
While the incident itself is probably not that big of a deal in isolation, it's interesting to look at the box score from that game and see that Tatum, Brown, and Rozier shot a combined 6-24. To be fair, Horford had a bad game as well. But the C's then lost two more roadies against supposedly inferior opponents in Orlando and Brooklyn to close out the trip 0-3, and so it's understandable why Kyrie may have been frustrated.