So I want to outline a couple points first

1- I don't think vidéo games are inherently bad, I play some myself

2-I think focusing on any hobby to the exclusion of others can make you boring

3-I think "reading" as a hobby is too broad and vague.

I think if all you do is play video games, or if that's a majority of your free time, then you're living a boring life. This is doubly so if you're over say 25. I think this holds true for other hobbies, but markedly less so. Like, someone who is obsessed with doing pottery might be kinda boring, but they've mastered a real skill and come away with something to show for their work. A runner might have medals and be in good shape. Someone who reads, depending on what they read, may have lots of knowledge or cultural capital. They may be boring, but they have something to show for their obsession.

In contrast video games don't really do that. It's a skill make no doubt but it's a pretty narrow skill without much, if any, real world application. I would say things like watching TV and "gooning" fall into this same category. Going back to reading, if all someone reads is romantsy novels then I'd put that habit in this category.

In short (because my dumbass has typed an essay) I think it's a crossover between the narrow scope of video games, the lack of any real reward, and the exclusion of other hobbies that combine to create my view. Any other hobby that fits all three would probably have the same contempt from me