Yes, absolutely. Look, to some people grunge is an attitude. To some people, it IS a sound (think dirty, fuzzy guitars). To some it applies to nearly any band that came out of Seattle in the early 90s, but to others there are only literally a handful or grunge bands. Some will say that Nirvana, the supposedly definitive grunge band aren't grunge at all but punk or postpunk...
So...different people use the word differently. If people want to call Soundgarden, Pearl Jam and the Screaming Trees all grunge bands in the same sentence, that's fine with me. But to me personally, grunge is more of a sound and a vibe.
For what it's worth, I was a teenager in the late 90s and did not live in Seattle. So obviously I was pretty removed from most of what got described as "grunge" or the seattle scene, which is synonymous with grunge to a lot of people. Again, some people would disagree with that.
Tl;dr Yes, although it is often used as a genre, it is more of a BS label and means different things to different people.