I'm making a website that gives free kittens and Bitcoins to anyone who has a HN username starting with a letter in the second half of the alphabet. You can't use it, which is a shame, but it would be wrong to deprive half of HN free kittens and Bitcoins, right? I mean, fairness is all well and good, but everyone likes a free kitten. I'm really sorry I can't make a website that everyone can access, but that would cost more so I'm not going to bother.
Your posts discriminate against everyone who can't read English. Unreasonable discrimination is the problem.
EDIT: granted, writing posts in English isn't arbitrary, but neither is installing small booths, there are good space-utilization benefits to it; it's unreasonable, because those benefits don't trump accessibility to people in wheelchairs.
Why would it be a shame? Life has always been unfair. Even if you were to make an accessible version of the website, people with no internet access wouldn't be able to access it so how is that fair? You can't really enforce "fairness" because it's subjective.
In this particular case however, the office had wheelchair-accessible rooms so I don't see why the booths had to be accessible as well when they serve the same purpose as the rooms.