Aside from that, not everything needs to be a business, and even then, not everything needs to be profitable.
Sure thing, but the article in question EXPLICITLY mentions "You should make a budget that supports having a good community, or you should find another line of work.", which means that one way or another funding is needed, unless you're comfortable with making someone read through kilobytes of drivel and spam in their free (or perhaps not so free) time.
Even then, I'd rather have one of those motivated by cleanliness service my area. Just the same way, I'll choose a forum that's not monetized.
I don't see how that sentence means that funding is needed. Plenty of forums exist with community moderation. Whether the person doing the work is compensated in respect and social connections, or money, doesn't really make a difference to me.
Why would they service your area at all? Are you sure that your area has people that would go around keeping the streets clean 8 hours a day for nothing in return? Not choosing a forum just because it's monetized is an odd choice to be fair, considering that this conversation takes place on a website that's, well... monetized.
Read the article again and see the context that the sentence was used in. Yes, plenty of forums exist with community moderation, but if the goal is to make a forum a place that is not going to become a disaster, a motivated and well compensated employee is the only solution. Otherwise you're relying on someones occasional contribution to the well being of the community rather than have things go smoothly at all times.
If capitalism is a value, then anti-capitalism is also a value. A lot of people believe the presence of capitalism on the web is fundamentally antithetical to what they see as its fundamentally anarchist/anti-establishment ethos.
Besides, the cost per month of running a small forum nowadays is less than what many people here spend on a single lunch. Not everyone is running a business or a startup.
Say it with me: communism.
Absence of monetization, to me means its a hobby project funded by you and not a business, that also perhaps means it has not kept up with the competition - think servers, performance, websites, mobile apps etc. Maybe avoiding ad based monetization could be what you are talking about but then you still got to pay the bills some how, so unless you monetize, I don't know how a business would survive. Considering this, I don't think its a surprise that your users are on the decline. Besides, doesn't everyone like to complain about ads online but very few really want to pay for alternative paid services anyway e.g. email, navigation, private messaging etc