Probably some sort of joke, or a bait and switch and when you contact them they say that they already gave away enough but are willing to sell some.Is this considered scrounging:
https://stlouis.craigslist.org/zip/d/saint-louis-free-firewood/7739245102.html#
I'd consider it if I could use it. I have more right now than I can use and I was going to sell a few loads this fall just to keep things in check. But with this much "FREE" out there in my area, I don't think that will be happening.
If it were me and I had the time I'd try to contact them anyway, who knows what will happen, especially since the next burning season is a long way off.