If you want to say "You are doing it wrong" that is okay. Even useful. In fact, at least in my case, I appreciate the input. But, if after doing so, you get hostile when asked "How do I not do it wrong?" then I really don't think that you have any claim to being taken seriously in your implied desire for me not to be doing it wrong.
Essentially, you are not obliged to educate, but if you are unwilling to educate than I am not obliged to give a rat's ass about your criticisms. Reducing hostility in a given medium is a two way street.