Purpose of EFY

I was always of the opinion that the purpose of EFY was to help people improve their English, especially beginners. Whar irritates me is that people make mistakes - I don't mean typing errors - and hardly anyone reacts. If someone does react and points out the mistakes a shitstorm follows, whereby the people who start the shitstorm also occasionally make mistakes.
I will give you an example as to how a mistake can hinder learning a language: 1) A teacher writes on the blackboard:" My sister drive a VW Golf" and asks what is wrong. 90% of the beginners only remember what that teacher wrote and not the correct answer when he points out the mistake. What would your answer be????
2) The teacher writes "Has your sister driven the car yesterday? Again at least 90% think this is correct and remember it. What would your answer to the mistake be?????
3)) The teacher writes "My father has driven a Ford since 20 years". The majority of the pupils remember this. Right or wrong? What is your opinion???
I could give you more examples. At the moment, however, I am waiting for your reactions, especially your views with regard to people pointing out mistakes.
Have a nice and healthy Friday" Griff