No, they shouldn't, but people who don't want that exact thing will not patronize their business either. The meme restaurant certainly has the right to say no customizations, and I have no issue with their first statement regarding allergies, because that is wise, but the 2nd and 3rd statements clarify their mentality and show where their allegiances really lie, and that there is no focus on customer service and a (possibly inflated) sense of self importance. They are certainly welcome to be that way. But if I read a sign that essentially said "we're not your mother, hire your own chef or go somewhere else if you don't like EXACTLY what we serve", then I'd probably head on out simply because of the attitude.