It was a great video by MedCram.com . Apparently the video is on that web site but may need a free account/login.
He blames it on a computer algorithm.
Here is his YT channel. videos designed for doctors and students but often informative for a general audience.
https://www.youtube.com/user/MEDCRAMvideos
I watch all the MedCram COVID-19 videos. I’m sure I’ve seen the removed video already. Fantastic youtube channel.
FYI, the study showing Zinc and HCQ that was reviewed by medcram and removed by YouTube was this:
Hydroxychloroquine and azithromycin plus zinc vs hydroxychloroquine and azithromycin alone: outcomes in hospitalized COVID-19 patients
https://www.medrxiv.org/content/10.1101/2020.05.02.20080036v1