Here are a couple of quotes that show why I am representing that claim in the way that I am, with bold added by me for emphsis:
"No. I see it as a place that WoTc feels can take some of the heat off them to create more content. I don't think they are
dumb to think that magically fan crafted material suddenly becomes accepted. If they allowed the stuff in AL then I would agree, but even they should know by now that
most DM's still do not allow fan created material."
"There's been quality stuff out there for years now through various editions of D&D. Doesn't change
the fact that lots of DMs still do not allow things outside of what comes from Wizards. 5th edition hasn't changed that attitude"
Between those two statements, it is very reasonable for someone to think that "fan created material" meant literally
all fan-created material, regardless of who the fan is or what kind of material it happened to be since there were no conditional stipulations provided or implied in any way. Similarly, it is very reasonable for someone to think that "things outside of what comes from Wizards" meant literally
all things outside of what come from Wizards since, again, there were no conditional stipulations provided or implied in any way.