but on balance do you not believe requiring full idenetification to make online comments or join a forum woudl civilise posters and foster morer decorum and restraint?...if he knew his contact data were visible in his post.
I don't believe it necessarily would.
There would first have to be some independent means of validating at least some of the personal information such as using a paywall in order to post here. Without this mechanism the use of full names and contact information could still be falsified.
Also, if someone lives alone and is isolated (like being long-term unemployed, living in a very remote area, or having no friends, neighbors, or relatives they socialize with) then having their contact information would be rather useless. If asking antisocial posters on here to behave doesn't work then calling them at home wouldn't help either. The only positive use of having personal information would be if a poster did something truly outrageous like threatened to harm themselves or others. Then their information could be useful to pass along to local police authorities or other emergency services. However, I don't see a situation though of the police being willing to raid someone's home because they bruised someone else's ego on here.
People in real life often have fallouts even if they know a lot about each other (sometimes because they know too much about each other). Neighbors being at war with each other is universal and has been that way since the dawn of humanity.
We also live in an era now where people "overshare" things online anyway. So posting names and contact information doesn't have a governing effect especially because in the real world social pressure is not as strong as it used to be. On sites like Twitter and YouTube there are many content producers who make it a point to go overboard on their opinions in order to attract more followers.
Another concern is hackers, criminals, marketers and data miners seeing any names and contact information as well. It would be openly available to them and all they would use it for are nefarious and/or profit making purposes. Heck, even posters on here could be incentivized to collect other people's personal data and try to sell it. And they would have no obligation to respect and protect the use of any freely given personal information of others even if the intent for providing it on here was to build a climate of respect.