One of the things this election has made clear is that for a lot of neurotypical people, mental illness a concept to be used when it’s convenient to them, and denied when it isn’t. It exists only when it makes their lives easier by existing.
If someone in their life says they have a mental illness, that’s inconvenient, because it means they might have to be uncomfortable, or to accommodate that persons’ needs somehow. So they deny it or set incredibly high standards of evidence that must be overcome before they’ll consider it. It can’t exist here because if it did that would be inconvenient.

But if someone they don’t know at all disagrees with them and they don’t understand why (in particular, see: liberals responding to Trump or Trump supporters), then the standard of evidence drops to basically zero. Without any study, evidence, or personal knowledge of the person, they’re willing to assume that person is mentally ill and vigorously defend that assumption. In this context, mental illness does exist, because it’s convenient. The othering effect is convenient, because Others don’t have to be analyzed. If you can other someone, your own assumptions and biases don’t have to be drawn into question because they exist.

When mental illness relieves these people of responsibility, it exists, and when it might add some responsibilities to their lives, it doesn’t. It is a tool to prevent them from having to do any actual work to help or understand their fellow human beings, nothing more.

To people who do this I say: you are the fucking worst, and I am not your fucking prop.