I believe the reason it isn't a tournament anymore is there is a new rule you can't play in two tournaments in one season.
Kind of, but also not all tournaments are created equal. I don't think the holiday festival was ever an exempt tournament.
Prior to about 10 years ago teams had a maximum number of games they could play. In the mid oughts the rules were changed and teams could play either 29 regular season games or 27 regular season games plus no more than four games in one multi-team tournament (four games, ergo "home tournament games" in addition to the 8 team on site brackets) for a maximum of 31 games. Postseason tournaments do not count against the limit. At that time they also eliminated the rule where teams could only play in two exempt tournaments every 4 years. When that rule was in place some teams would play the Holiday Fest when they weren't eligible for exempt tournaments.
So the Holiday Fest as a non exempt 2 game tourney back then counted as two games. Two games that can be played at home to generate significant revenue, instead of giving away one of those games to play in an exempt tournament. Why is it not exempt? That I do not know or remember.