I like watching football, even if United aren't playing. In fact sometimes it's easier watching football when I don't care about the result, like when United aren't playing. I like watching Ronaldo, always have, even when people wanted him shipped out for having no end product, for being a diver, for being a winker. It's a shame he doesn't play for us, but players come and go, and he's just another one.
As for it being something uniquely modern. It really isn't. I remember English kids wearing Brazilian shirts with Pele, or Ronaldo, or Romario on the back. After Best left us, a lot of people went to matches just because he was playing. We hear stories of great players of the past like Dixie Dean or Tom Finney because they stood out, even to people who weren't fans of their clubs. And that's from before Youtube and loads of live televised football - they became famous on Pathe news.
For me, a match is always more interesting if there's some kind of United link, one of our old players, someone I want us to buy. So yeah, of course I'll watch Ronaldo as well as Real Madrid V Liverpool tonight.