Never worry about making snap calls to shoves. Unless you have the nuts you are always entitled to think it through.
This guy was obviously upset that you have him beat and is taking it out on you. Which is obnoxious. It is not unusual though. When people are slow rolled (which is how he felt) they typically focus on the slow roll as if that is why they are devastated instead of on the fact that they lost the hand and are getting knocked out of the tournament.
The thing to glean from this in the moment is that UTG is likely tilted and may come after you moving forward if he buys back in and lands at your table. When I am in a situation where a guy is reaming me out after I have busted him I never escalate the discussion. I generally say "Thank You" as if his insults are somehow helping me develop into a better person. It often just ends the conversation. But the last thing I want to do is get into a fight with a player who has just been eliminated.
The other thing to note is that while it is extremely unlikely, UTG can have a flush that does not have a card bigger than your T
so, in addition to hitting a boat on the river, you could possibly hit a bigger flush.