The sad fact is that violence against disabled people is normalized in our society. It's a revolutionary act for a person with a disability to boldly proclaim they don't want to be put out of their misery. It is an act of defiance against social norms for a family member to say they don't feel burdened by someone they love, and would fight tooth and nail for that person to remain in their lives. It is considered insensitive to tell someone who loved the movie Me Before You that you think it sends a dangerous message.
If their existence wasn't such a burden, it wouldn't have been necessary to murder them.
People with autism are far more likely to be the victims of spousal abuse than the perpetrators. I should know.