I encountered "Econ101" many times and it never made sense. I don't recall it ever being used in my presence for a basics course in economics . The others always used it to assert that their economic favourite idea was undisputable and correct.

Stuff like
"stimulus packages are always a good thing, that's Econ101", for example.
"stimulus packages are always a good thing, that's basic economics", for example.

So blame me for misunderstanding the term if you want, but I blame those who distorted its meaning instead.
No one blamed you for misunderstanding the term; I called you on your manners in presenting the issue--as did John T.

Tom