1) Post to the general public. There are lurkers that are part of your audience.
2) Respond to ideas, not individuals
3) Dehumanize: Anyone responding to you doesn't know you.
4) Don't get involved in the back-and-forth sand trap
5) Recognize the Peanut Gallery* for what it is. However, feel free to use the rare useful idea from the Peanut Gallery.
6) Limit interaction that's on a personal level. Avoid communicating many details about yourself. These people are not your friends.
*The Peanut Gallery expression originated with Vaudeville where cheap seats were offered and peanuts were served. It was an act of socially consciousness, allowing lower class people to be exposed to cultural endeavors. Those lower class people would sometimes shout unqualified opinions about the performance and throw peanuts.
https://en.wikipedia.org/wiki/Peanut_gallery