Forums ebb and flow, and those that are niche focused or one-topic driven, often lose traffic over time. I belong to a runners forum for example, and it used to be so active about five years back, but with Instagram, Facebook, and other social media platforms, forums are dying off. Forums that tend to attract a lot of traffic, are those where there is a wide variety of topics being offered. I think this is why the runners forum is dying down, because there aren't enough ''off topic'' threads to attract a wider audience. Granted, one could make the argument ...well, it's a runners forum, which is designed to bring mainly runners together, right? Sure but, in the end, even runners want to talk about something other than ...well, running.
Same with science forums, or any one-topic driven forum. I wouldn't take it personally (if anyone is)...it's just the nature of forums, I think. I'm glad to see that this site is still hanging in...some other science sites have virtual tumble weeds blowing through.
I agree about the one topic forums. I sometimes check into a guitar forum. It's small enough that the people "know" each other online and therefore it's polite.
Someone started a political thread and at first a few people could do nothing other than appeal for a moderator to "close this thread!" but people continued to be polite and the others are beginning to realize that you don't have to read a thread if it trigger you as it doesn't trigger most people.
If all you can talk about is guitars after while you just don't have any reason to stop by as often.
When I think about moderation I think about two very specialized forums. They are about shaving.

Straight razor shaving, double edge blade shaving, shaving soap, sharpening straight razor blades, etc.
It couldn't be more specialized. However there are two such forums. One has been there longer, the moderating is very authoritarian, the members are even a little that way (those who stay) and it doesn't have a lot of traffic anymore.
There is another one that is 10 times bigger, it's way more polite, little moderating is needed and as I said there is way more traffic and way more topics. I don't even know who the moderators are as they are more or less transparent.
Both sites should have the same amount of traffic and the only difference is that the smaller forum is just over-moderated and the moderators are in everyone's face and if a moderator has an opinion on the best way to do things, everyone else either has to agree or they are "attacked". It just isn't a pleasant place to be so most people eventually leave (including me) and therefore the few people who stay are all the same type (authoritarian).
I think there are a lot of lessons here for how to run a forum and how not to. I've seen the same dynamics play out in other specialty forums. The heavily moderated ones don't do nearly as well. The less moderated ones have far less need for moderating. They aren't the ones where everyone is out of control like you might expect.
If some poster is a jerk, they just don't get a lot of responses. Which is a far more effective way to deal with that problem. More effective than a convoluted banning system, annoyed moderators dealing with people they don't like, etc.