I might be in the minority opinion, but it sounds like the TD was somewhat out of line.
Players have no obligation to accept an undo. As a TD, I expect people to accept them when they're valid, but I will not force their hand. Having said that, I do not feel that a single sarcastic remark aimed at an opponent for not accepting an Undo is grounds for removing a player from the tournament, unless the tournament was specifically listed as "zero tolerance for rude behavior" or something to that effect. This is the same as saying "You were lucky to make even though you misplayed" - it is rude, yes, but not to a degree that requires expulsion.
If the remark in question had used foul language, implied cheating, or anything similar, I do feel that an immediate removal from the tournament was in place - but I also feel that it is a director's obligation to inform the player of why they were removed, in all situations.
Of course, that's just my opinion