By that logic, should children in wheelchairs not be allowed because theme parks, 'classically', involve walking long distances? Should braille be removed because theme parks typically involve reading and sight seeing? That people with disabilities are not going to experience something in a way that is 100% cookie cutter and archetypal seems like it's pretty much part and parcel with what the definition of 'disability' is. Why should lines and noise be considered the 'core' experience of a theme park, as opposed to meeting Mickey and Minnie, riding Small World, eating in the castle, watching a parade, etc.?
Also, keep in mind that a lot of kids on the spectrum have a tendency towards “special interests” or are passionate about only a few things, so it’s not always a matter of just taking them somewhere else that a neurotypical kid would find fun. Options are often much more limited.
Here's the thing. If a child was miserable throughout the entire experience, yes, of course it would be horrible to drag them through a theme park. But of all the potential abuses of DAS out there, this one strikes me as extraordinarily unlikely - “selfish” parents dragging an escalated, tantruming or possibly aggressive child through Disney so that they, the parent, can live it up taking selfies on Thunder Mountain in their rose gold ears. That sounds like smashing your hand repeatedly with a hammer to score painkillers. I’m not saying no one does it, but if they do, they have a serious problem. Trust me when I say that dealing with autistic meltdowns is... no one’s idea of a good time. That doesn't mean that parents don't have different stances on the 'right' way to raise their child. Some parents will be big on getting their child out and exposing them to the world even if it's really hard, some will really avoid situations that might be triggering for their child. There will be a range of opinions on that. But what I don't see is a ton of parents who will drag their child out to a place where they will be pointlessly escalated because that would be a fun thing for them, the parent.