Forums are a lot like school, bunch of people all in one place, some you get on with, some you don't, different backgrounds, experiences and so on. The biggest difference between a forum and a school is in this forum we're adults and we have far greater understanding that when we communicate with each other it should be in a respectful manner even if we don't agree with them (difference of opinion) or we know that they are completely wrong (knowledge). There are ways to approach and 'talk' to people on a forum and sometimes not everyone gets it right.
Of course there are ways to respond to someone to tell them they are wrong without coming across as rude and abrupt or dare I say it, in some instances pretty condescending. I don't believe anyone wants the answer sugar coated, they've asked a question and they would like an answer because they want to learn. People do need it pointed out where they are going wrong, otherwise what is the point in asking a question if you can't accept the answer. We aren't all teachers or trainers, but as with all things in life, there are ways to get people to understand and a bit a kindness in that response goes a long way. And by kindness I mean don't make them look like a fool.
There are always those posts that make you roll your eyes, wonder where the hell they did their training, completely shock you and so on. How we respond to those posts, if we do at all, could be the difference between helping them as a professional or have them continue to butcher someones nails/skin/hair.
I am a lover of a sh#t sandwich myself
I find it's much more productive than constantly being negative.
As for bullying, well I think that's already been covered, it doesn't need 4 or 5 people to say the same thing. And if you are going to tell someone they are wrong then follow it up by telling them how to rectify it, whether that means explaining how to do it right, sending them back to their trainer, going back to their books, looking at threads on here, explaining that the basics need to achieved before they attempt the technical side of things or suggesting further training is required. This forum isn't just about answering questions, it's about supporting each other and helping each other become better industry professionals.