I'm an idolfag but not really a unicorn or interested in seiso. I really dislike how the two are conflated even though it is true for a lot of retards.
To me, idolfaggotry is about supporting an oshi that has some type of tangible (not subcount related) goal that they're progressing towards. It's refreshing compared to your typical streamer life trajectory of rotting away in a room playing video games with nothing in particular to look forward to, retelling the same old stories from before they became full-time streamers and becoming less and less interesting over time. I really only want to watch people that have dreams and shit. If my oshi dropped everything she did except streaming games and never tried to make high effort content, I might as well be watching DSP.
In old school idol vocabulary, oshi [押し] literally means 'to push for' as in to support. It's not a synonym for waifu. Having an oshi could be considered living vicariously through other people's achievements but hey man, it's my entertainment.
I think most real life idolfans are closer to my perspective than gachikoi. If it were all about delusional simping, idols wouldn't bother putting in the effort to do all the things they do that don't bring in as much money like original songs or dance training.