I'd estimate there's perhaps 100+ active members who use the Tavern and Metal Discussion boards, including the half dozen or so moderators. All the other registered users keep themselves to the Trade or Musician board. There used to be a section called the Symposium equivalent to our Deep Thoughts board, but sadly, the userbase wasn't up to the task of keeping serious discussions, so it was eventually merged into the Tavern.
You'd think a website devoted to documenting music where lyrical themes cover a myriad of taboo subjects would attract scores of politically incorrect malcontents, but a cursory glance at their general threads reveals a different reality.
To get a better insight onto the state of the discussion:
Until around 2009, Metal-Archives allegedly used to have a much stronger plurality of conservatives, social Darwinists and outright Neo-Nazis. So many of those old threads were gone, so it's difficult to tell exactly when was the turning point without tormenting yourself going through every solitary thread and scanning all the posts. Allegedly, the moderators wanted to elevate the quality of the board's discourse, which meant banning a huge swath of right-wing radicals. The resident right-wingers weren't too sharp when it came to debates, so many lost the arguments when taken to task. Once PhantomOTO became promoted as a forum moderator, he actively berated, mocked and even edit the posts of users, especially right-wingers, he didn't like with impunity. He left around 2011, but at that point, he had set a precedent for others to follow. Progressives, left-liberals and leftists gradually dominated the discourse around 2011, and several were able to keep enough of a composure to be promoted as forum moderators.
Since then, the discourse has gradually deteriorated into contests of sneering and virtue signaling. If I had to create a shitlist, the worst offenders over there are Morrigan, OneRodeToAsaBay, iamntbatman, Grave_Wyrm, Erosion of Humanity, failsafeman and much more. The site hasn't completely gone mad, though. Earthcubed still posts there, and his opinions are always highly informed and well-researched. He's a pleasant foil to all the populist progressive hysteria rampant on that site. The communist John_Sunlight is also enlightening to read, albeit for different reasons. Of all the leftists, he's by far the most civil one.