If you have a disability then you might be looking for someone who has a similar disability, or at least someone who isn't going to judge you by your abilities or any lack of them. Improved technology and a good support structure mean that disabled people are actually more able than ever before and there's are no limits to what can be achieved.
There's no reason for anyone who is physically or mentally impaired to feel they cannot enjoy a fulfilling emotional and sexual life. Online dating sites designed for disabled people are run by those with the required understanding and empathy.