Different contexts are different. While at an airport, few are likely to connect his face with his website and have it known that he has a disability. Even if he's talked about it on his site, that doesn't mean it's automatically known to every person everywhere, humanity is not a hivemind.

Furthermore, he's attempting to advocate for others who may also not want their disability known. He gives up his privacy in a certain setting in order to (hopefully) allow many others to never have to give up theirs.