So 99 music categories, 32 music video categories, assuming your commitment to objectivity, the low estimated average of the length of each song, and the amount of videos/music you listened to.

With the low estimated average song length at 4 minutes, with 15000 songs, 131 genre's, you would have had to listen or watch 2 hours and 40 minutes of songs per day, without ever taking a single day off, so that means you as a lone person watched or listened to 114 songs per genre with almost 300 hours of music per genre to stay objective.

But even with the minimum you're saying you searched for and listened to the songs through Reddit. Which means you've actually spent a considerable amount of time finding the songs. Even if it's 5 seconds between each song without ever taking any breaks, that means you've spent almost 21 hours just finding these songs on Reddit. Not including the amount of time spent scrolling through subs looking for new songs.

It'd be believable or even have the appearance objectivity to have a sub of a group of people claim to do that much research over the course of a year. One person? And 90% of the content is on Spotify? But all found by going through Reddit? Idk. Seems to be an unlikely claim.