This gear is such an outlier compared to his other gear and general interests. Final Fantasy, Sega and Capcom? All seems pretty congruent. You've met guys where that's their whole shit. There's also plausible deniability on the grounds of nostalgia, like you're not that big of a nerd. But this cancerous horsepiss that did irreparable damage to two entire industries of a whole country's arts sector? It just don't add up.
Undertale is fine, 4chan is not a monolith but this website loved it when it came out.