Not to put too fine a point on it, because that is not at all what I'm talking about, but, asking an organization what, if anything, can be done to help you personally combat your allergies, by not forcibly including them in your food source or immediate area is different then affecting hundreds of others to accommodate your situation.
I worked in a school system once that had a family with a child that had a severe, severe allergy to all things related to peanuts. They didn't ask, but demanded that the school accommodate their child's situation even though any exposure could have easily caused the child's death. The school considered many ways to make sure that no peanut based products would be used in the school. That in and of itself is a huge challenge. They had multiple meetings with experts and had a committee devise a plan to make that happen. Then they ran into the road block. The parents demanded that no child bring anything peanut related to school. OK, maybe doable, but chancy at best. Then up the anti to say that the 200 children also in the school could not have even the slightest contact with peanut products while away from school. Even the small particles on their breath could cause a reaction to the child. Everyone could understand the concept that the parents were trying to make this young persons life as normal as everyone else by having them be part of a normal school system. But the school could not guarantee that they could control the environment outside of the school building and had to tell them no. What the parents were asking was having a profound affect on hundreds of others that did not have that particular problem, but now would have to live their lives as if they did. The school had to say no and braced for a lawsuit. The parents lost due to the fact that some situations are not in the control of others for a number of reasons. One of the largest was how many other people were directly affected by that accommodation and the fact that keeping young children away from peanut butter, when they personally have no reason to be deprived of it was not a reasonable request and almost like trying to get a fish to live out of water.
A place like a theme park has a far less requirement for attendance then a place of education. One is a luxury the other is a necessity. Yet, it is within reason to basically describe a particular problem as disability that cannot be accommodated in a way that wouldn't cause hardship for others.