"In this book I have used the term ‘Down syndrome’ often you will see it written as ‘Down’s’ with an apostrophe ‘s’ — this is more commonly used in the UK and the non-possessive used in the US. The term ‘Down’s syndrome’ is what is called an eponym, where something derives its name from a person; in this case the physician John Langdon Down. I personally prefer the non-possessive spelling as it’s not as if Langdon Down had or owned the syndrome and this type of eponym is falling out of use more generally."
--- The Politics of Down Syndrome / Kieron Smith
Calling people "goondus" for using the term "Down Syndrome" just shows you are not just ignorant but so ignorant of your ignorance that you can be truculent about it (aside from the other problems with truculence; if you want to be truculent, at least be right).