1990s culture in general, but especially the Britpop era is pretty cringeworthy when you look back. It was basically a marketing concept based on hype and a supposed kickback against US culture and influence. It was all manufactured in reality, by music executives and the media, the quality of the music that came out of it wasn't that good.
Oasis were a band that were for young people that weren't really into music as such. A lot of their fans were school kids and teenagers. I guess their music attracts kids from new generations and that mixes with the nostalgia of the older audience. Personally, I haven't get anything against them as such. Noel Gallagher was pretty crafty with doing various things - a lot of his songs involve a blatant rip off from other material. A lot of their gigs were notoriously poor as well.