A big part of my life is dedicated to advocating for my own needs. Why? Because if I don't do it, no one else will. I have the strength of personality to face down asshattery again and again without getting too discouraged. Angry, yes, but I don't give up easily.
There comes a point, though, where I just shut down. I cannot have the same discussion in different ways again and again. Once you start looking for loopholes, start argument-from-toning (hint: I'm an adult. "That behavior in trying to get an immediate need met is inappropriate" is pretty much the most asshatty blame deflecting thing you can say. Ever. If you have ever said this to someone advocating for herself, climb a rope and let go over a pit of spikes. If you cannot yet climb a rope, I will teach you), start making excuse after excuse, I cannot continue dealing with you. If you staunchly refuse to listen to my well educated thoughts on a matter, then beating my head against the brick wall that is whatever topic is at hand isn't something I am willing or able to do.
You don't win if I'm not able to continue a discussion with you, though. Giving up on talking to you doesn't mean I gave up on the issue at hand. It means I am looking to route what I need around the false roadblock you set up. You don't think disability access is your problem? Sucks for you, since legally you are wrong and the court will cheerily tell you otherwise. You don't think that I know the first thing about my medical crap? I want a second opinion, from someone competent. I know you aren't competent because what you told me is the exact opposite of what the technical literature told me. Oh snap.
Once I give up on you, you are probably in for fury the likes of which hell hath not seen. I have other resources. Don't make me use them. Yes, I get overwhelmed, but I have that soul of steel that only lets me wallow in that for a few days if the issue is truly important to me. You only think you want me to give up on you.