So these are Wii Virtual Console games returning, yes, not new Wii U Virtual Console releases of the games? The two are different things.
Anyway, it's pretty much the same with the Wii as it is with Steam, the Xbox 360, or the PS3 -- if you already own and have a game which was removed of course you can still play it... but no one who doesn't own it already can, because it's not being sold anymore. But no, people who already bought the game don't have access blocked or something... unless it's an MMO of course, in which case shutting it down does kill the whole thing, but there aren't many of those on consoles of course.