Looking past the inherent idiocy of this, the person who posted it is most definitely on government assistance of every kind, has a job on the level of a teenager's after school job, and lives with her parents.
This person posted a video about parents teaching their babies (who are not deaf) sign language. Apparently he views it as cultural appropriation.
I think of appropriation as when a dominant culture adopts a watered-down (or in some cases stereotyped) version of some of the features of a minority culture to serve their own ends but without any understanding of the complex minority culture that they are drawing from. In as far as that minority culture is threatened while this process unfolds, and in as far as the dominant culture remains unconcerned with or ignorant of that threat as they continue on, this process can be destructive. It's like naming a Little League team the Indians or celebrating Thanksgiving with a pilgrims and Indians skit without having any consciousness of the genocide that happened to the indigenous people of the Americas. This isn't to say that ASL can't be taught to hearing children. I think if it were done in a way where they actually learned ASL as a second language and could communicate with actual Deaf people, that would be awesome and not at all appropriative or destructive.