"neither can an american" - Humor with irony, all in one pithy little sentence!
Actually, don't joke about that! Have you ever heard a Polish teacher try to teach English?
Those that learnt American English.... omfg! It's not funny. They should sue their teachers...
Imagine if I was teaching Polish in England, except I'd learnt Czech and tried to pass that on as Polish....
If you can understand that then you'll realise why the poster posted that comment...