When Gransnet was fairly new (eight years ago) another social media site started up, with a similar name, aimed at the same people. It was heavily moderated (unlike Gransnet, which waits for members to alert them before moderating posts) and it put a lot of emphasis on "nice" posts.
To be quite honest, I felt it was BORING and not worth visiting, and that is from me who doesn't like sarcasm and personal insults. Their members must have thought the same, because it got fewer and fewer posts, and eventually faded to nothing and closed down.
Most of the threads on Gransnet contain no nastiness at all, and almost all posters write sensibly without blasting anyone who disagrees with them. On some subjects, posts get polarised and posters start to be heated.
The secret is if you don't like to read their quarrels, leave and go elsewhere If you were the one on the receiving end, go back and read what you said yourself, and see whether it could have been misinterpreted by someone who didn't know you and couldn't see your face. If it could, post at once saying something like, "I didn't mean it as you have taken it, I meant . . . "
At least half of the fiery exchanges on here are caused by someone getting the wrong end of the stick and misunderstanding. A lot of the others are between people who fell out years ago over something completely different, but are still sniping at each other automatically. Leave them to it and go to a different conversation.