I'm not sure about the allegations, but this certainly does not match my experience -- I have seen an incredibly diverse set of people in my FYP feed.

(I wish YouTube had content discovery like TikTok -- YouTube seems to always want to steer me to either something that's an exact clone of the last thing I watched, or something that's just dumb and super-popular. TikTok is amazing at ferreting out all kinds of veins of interest. It's great.)