You both have good points. One interesting aspect is that this volunteer labor is actually contributing to what is making the product valuable in the first place.
You could volunteer to do QA for a software company, or volunteer to clean the floors at a bank, or volunteer to work on an assembly line… And we’d likely criticize those businesses for taking advantage of that labour if it were systemic and widespread.
On the other hand you have open source projects which are freely licensed for huge corporations to make tons of profit from, and all we expect is that they give something back (but we don’t even hold them to that).
It’s interesting to think about where moderation work sits among these.
The reward for the work is the result of the work. For these communities to exists, there must be moderation and for many people the existence of said communities is worth the cost in time/server costs. Reddit selling stock off the backs of people who perform free labor for them is a problem, but someone who sets up a lemmy/mastodon/whatever to host discussion about the things that they care about is not a slave just because they don’t demand monetary compensation or sell your data. The lack of monetization isn’t a bug it’s a feature.