[depressedpanda]

Another comment suggested you try to appeal to empathy. It might work, it might not.

If it doesn't you can instead appeal to the bottom line. Tell 'em that they might get targeted by an accessibility troll: https://www.wrightlawgroup.com/blog/attack-of-the-ada-trolls

As far as trolls go, I consider these fairly benign, as their behavior actually promotes something good; we got hit with such a lawsuit, and all of a sudden a11y became a big thing as our CEO didn't want to give a dime to those 'greedy assholes'.