Nah, I think you’re right, and I’ve seen others express this as well.

I mean, fiction genres aren’t any more useful than any other category we try to put things in – IMO, a very limited usefulness. But the lack of any clear explanation for how a lot of the things in Tron happen– and the pervasive hints at a magical or supernatural explanation – certainly make it feel more like a fantasy, perhaps a modern retelling of a fairy tale, within a technological setting.

This goes more for the original movie than Legacy, though. Neither one has very clear science, but the aesthetics and themes common in fantasy are much more prevalent in the original.