Ah, yes. The site that has a thousand reasons why the band you're looking for isn't "metal" enough to be in its database, but then has an entry for Rush:
I mean the line needs to be drawn somewhere, right? It's not that a band isn't "metal enough", it's just that they have a bunch of rules interpreted by mods and if it doesn't fit those rules they make the editorial decision to exclude it. It's impossible to have some kind of perfect description anyway.
Rush were added probably in the first year or two of the site's existence, so they probably kept them on their for nostalgia.
It's a little puzzling that Blue Oÿster Cult isn't there. There's a historical case for them and the post-1980's records have recognizable modern metal.
https://www.metal-archives.com/bands/Rush/1206