Ignoring trolls is good advice but that alone doesn’t solve the problem of losing new/prospective members who are turned off by the prevalent bickering and posturing.
Disagreements and opposing opinions can be important catalysts to introducing new ideas and learning new stuff. If only folks could state their opinions and then get out of the way and let others do the same, without trying to prove they are smarter, more experienced, or have a monopoly on the one true path. The train is off the rails when those with opposing opinions are accused of having poor hearing, inferior systems, poor critical listening skills, an inability to understand science, or any of the other worn out ad hominem arguments we see here too often. More active moderation might help, or possibly moving contentious threads to a separate forum where more aggressive debates are tolerated. Ideally, those who want to aggressively argue their points would start their own threads specifically intended for those who want to debate a certain issue. OTOH, if somebody starts a thread with the words “snake oil” in the topic, nobody should be surprised if the arguments turn contentious.