Traditionally hockey is a sport for the elite. Especially rich people play it, so it doesn't appeal to the average Dutchman. I really think cycling gets more attention on tv, which is pretty weird if you compare the performances of the Dutch in hockey and in cycling
But as said before, it's still pretty much a sport for the relatively rich people. That's why teams in small towns can be topteams (Den Bosch (women), Bloemendaal) I think.
Judo is very different to this ones. Judo is pretty 'normal' to do, although not very much people do it in Holland. But kickboxing and the other fight sports don't have a good image around here. I know in kickboxing we have some guys who're top of the world (I think so, but I don't really follow it actually). This guy Badr Hari is pretty famous in Holland, but not because of his performances in the sport actually
He has beaten several people in public, he can't control his aggression. And he's dating the ex-wife of Ruud Gullit.
So yes, it's a niche and it doesn't have a good image. That's because of some things happened at kickbox galas, where it became very violent. I think it's mostly played by immigrants, I think the most Dutch top kick boxers aren't originally Dutch.