If e.g. YouTube recommended you the best items from all countries, you'd have a very bad time and would be unable to understand almost all media.
The same applies to age and gender. If you were only recommended items relevant to 90 year olds or 9 year olds, you'd have a very bad time on YouTube etc. Just because you don't notice that your media is implicitly sorted doesn't mean it isn't happening.
a few examples:
https://news.ycombinator.com/item?id=23640033 (9 year olds, RU)
https://news.ycombinator.com/item?id=24431001 (CN, IN, RU, US)
https://news.ycombinator.com/item?id=24398456 (JP, SU, US)
https://news.ycombinator.com/item?id=24156310 (caucasian variety)
Now I realise I should seek out 90-year old appropriate programming. Anyone have any hints?
Bonus clip: https://www.youtube.com/watch?v=y2fNVztaC58
Edit: After a quick calculation, I realise I have watched music from 1943: "Blood on the Risers", "Lili Marleen", "Zog Nit Keyn Mol", "Bella Ciao", and "Катюша" are all suitable for 90-year olds to have encountered as young teens.
https://www.youtube.com/watch?v=hHLRFlKPNMA (with subtitles)
and it's not as if 80s europe wasn't full of foreign-language entertainment:
https://www.youtube.com/watch?v=TDOf41Xwrc4 (caveat for US HN'ers: it's a european music video. No blood, two beasts, some breasts.)
(The 80's were big hair and shoulder pads, no matter which side of the iron curtain.)
I mean, I heard from a friend, who certainly wasn't involved with making any of the stuff, that that's how such sites operate.
(Today I had some trouble searching for "Micro-abrasive Imperial Lapping Film" until I expanded the acronym. Doesn't Google realise I have a connector tip to polish?)