How people can't understand sensory issues

I am still amazed after I tell people that Pozzy has sensory issues, they brush it off.  Act like it's all in my head or they will not take time to understand that she has sensory issues!!! I don't know if some family is in denial or if its an old school thing where they just don't get it.  I have no idea but my child is different , i don't treat her different but somethings she does , she does need a little different treatment.  Ugh it just irritates me!!!