Edit: I was going to post only this tweet, but I couldn't get it to fit in the character limit. It now occurs to me it might be unkind to circumvent the removal of all but one of Vi Hart's videos, presumably in response to an adverse experience. However, I also think the withdrawal of previously published videos is a problem with streaming video platforms.
I suppose I should point out the one remaining video (On Gender, from 9 years ago): https://www.youtube.com/watch?v=hmKix-75dsg
I don't know exactly what happened, but judging by the video that remains, maybe gender-related harassment prompted ViHart to make the mathematical videos private.