This was also true of the American Civil Rights Act and the Voting Rights Act until courageous people like Dr. martin Luther King and Rosa Parks came along and said enough is enough! The truth is that Rights do not become part of the culture just because they are written into law. That is only the first step. We must also take the responsibility for ensuring those rights are enforced. If we causally walk away from that responsibility, then we can only blame ourselves for the resulting apathy.
Date issues aside, this is one of the reasons I've chosen to not hide my AS/D. The only way to change things, socially, is for people to start standing up and asserting themselves, instead of hiding.
Now, I don't necessarily announce it on most applications or in most interviews, but I also don't hide it (and I have started answering "yes" to the voluntary disclosure section). All it takes is a simple read of my blog to find out.
I've also found it more detrimental to try to hide it, because to hide it means to spend all day attempting to "pass," which is exhausting (especially in an office environment). That pretty much has invariably led to a meltdown to one degree or another. So, instead, I choose not to actively hide it. One of the things that has helped it be pretty much a non-issue is that I made a sort of list (it's not a concrete one, just in my head) of the work conditions in which I will and will not work and what environmental things I need to be effective. This allows me to filter out the bad environments before it even comes up, because it doesn't matter whether I hide or not, bad environment == crash and burn within about 6 months.
Now, I know I'm privileged by the fact that I'm a software developer, and so, my skills are very much in demand, and the field/community are riddled with mental health and other stuff, making it less of a taboo in the community as a whole. That, in my opinion, makes it all the more important that I don't hide, because not everyone is in a position to do the same, nor can they ever be until those of us in better positions in which to do it become more prominent.
You're damned either way IMHO, if you declare you're disabled you're open to discrimination, if you don't, get the job and then they find out about your disabilities, they could fire you because technically you "lied" in your application, although under the Equality Act 2010 if you're terminated purely for having a disability you could, in theory, sue the crap out of the company for blatant discrimination.
I can't speak for other companies, but in the US, the disability disclosure part is voluntary and has the option to not disclose. As a result, employers cannot (technically) fire someone for "lying" on the application regarding disclosure. Most states have a law that allows employers to fire employees for no reason (basically, employment is not a hard-and-fast contract that requires a particular reason for termination from either party, though it arguably favors the employer), which does complicate things in that way, but if you can prove it was due to discrimination of disability, you can fight back.