Yeah, sorry, I came on way too strong with that language. To be fair, the "angry F-U breakup text" is what I said would say, not OP's description of what the guy said. I hate it when people are so cowardly and self-centered that they can't bother to say a proper good-bye when they stop feeling a romantic connection. With the exception of people escaping abusive relationships who could be hurt or talked into staying if they don't ghost and block, I think anyone who ghosts a dating partner without warning is being disrespectful, mean, inconsiderate, low-class, and the list goes on.
I still don't think it's necessarily a red flag. OP told him she'd be on vacation, but NOT that she would be unreachable by text. He tried to be thoughtful and attentive by reaching out to her, and it certainly appeared that she had ghosted him. I think many mild-mannered people would jump to that same conclusion. If he does have anger management issues, it will become obvious when (if) they date some more, and she can break things off with him then.