A powerful story and has many life lessons.
Yes, it is common for us to treat others differently who are different from us. It's human nature that needs to change for a better society. It starts with me.
I worked with DS individuals too. Some of them treated one another differently. Many knew and understood class, sex, race, high skills, etc.
I observed that children with DS with wealthy parents and community tend to do better in life than others with average incomes.
But, it's still hard work to raise a child with DS, and many parents choose not to share their real-life when their front door closes.
Well done.