I am also a relative newbie to GN, although I have been posting for several years on some other internet forums; one of which is USA based and is tightly moderated, so you really have to mind your Ps and Qs, and another is a UK-based current affairs site where robust personal attacks and swearing are considered perfectly acceptable - although most posters are reasonably polite. I think GN is a brilliant site which strikes a pretty good balance between under- and over-moderation. Mumsy, as you become more familiar with posting on the internet, you will find that differences of opinion are not unusual on online forums (as in RL). Sometimes things do get heated, but I have never noticed any posts on GN that could be described as “vile” and if someone objects to a particular post they are free to report it to the mods, who will make a decision on it, based on the site guidelines. What I have seen on here is a friendly online community, full of warmth, wit, compassion and good advice.
You seem to have signed up for GN and then started to have a look around at the various threads, but it is generally best to just read and get a feel for a site for a little while before you sign up, so you can be sure it is somewhere that you would feel comfortable, and perhaps, in this case, you may have put the cart before the horse. 