I actually feel it does not go without saying that you are sympathetic to a parent of a "disabled" child based on the condescending tone of your message. I also wouldn't label sensory issues as a disability, just a different approach in life. Now, as her mother, and I do assure you I am in my right mind, Disney is the ONE place we can go where she can be free and experience joy and magic. We can plan our days, we know what attractions she can and can not handle. We know her triggers, we know what her cues are. We take many planned breaks, we take many detours, we miss many fastpasses, sometimes we only get in half a day and she needs to go back to the resort and swim or chill in the room, but it's all ok, because she can enjoy the vacation just as much as the rest of us. We also get her a stroller, it's like a little cocoon for her. It's quieter, it's shaded, it has her security blanket and she can check out while we walk to the other side of the park.
So yes, I also deal with the looks of disgust that my now 6 year old is in a stroller too. She looks "normal", she acts "normal" most of the time, so it's a good lesson to not judge anyone based on what you see 
Like the poster I quote below, loud, intimidating chanting groups are not something that's easy to prepare for. We actually AVOID those times of years specifically because of them. In four trips we've been lucky and not had an encounter. I was taught respect. I wouldn't use my "freedom of speech" to cuss off everyone I saw or use it as an excuse to be rude and obnoxious. I don't expect everyone to accommodate my child, we are teaching her what she needs to know to live in the real world. But I would appreciate a certain amount of respect in return. If she's melting down in line, I leave, I don't expect other patrons to deal with her behaviour. Chanting is just plain unnecessary.