> You mean "volunteering to keep a community forum polite and productive".
Both of those things can be true.
The reality is those communities--which only thrive on Reddit because of effective moderation--are built on a private platform whose primary method of generating profits is to monetize the attention of those community members.
So, yes, those mods are absolutely contributing free labour that Reddit is turning into private profits, and that labour comes in the form of volunteering to keep those forums polite and productive. Whether or not that's a reasonable tradeoff is up to each individual, though I have to confess I don't personally understand it (despite, in the past, benefiting from it). At least my day job pays me for the labour that they monetize.
And now Reddit is taking a dump all over those free labourers by taking away critical tools that they use to make those forums polite and productive in the first place.