Among many other accusations against his person which can be maybe up to debate, one accusation stands out here in Geneva, Switzerland - he repeatedly used pretty bad violence against his youngest son to the point he is badly traumatized for life, having issues with basic functioning. That's suicide / self harm / bad violence material later in life. I have absolutely 0 tolerance for such piece of shit, you don't need to be a parent to see him as absolute scum of this world, and no suffering too great for him.
Maybe his work and product is stellar, maybe not, I am beyond caring. Child beaters can do whatever stuff they want, they are still primarily child beaters. The fact that russians use it so desperately for their war in Ukraine doesn't make it any better in my eyes. These are eyes of regular Joe mind you, just like most of this world.
Point me to other child beaters who also created something popular and I'll happily toss their shitty products down the drain.