I don't see these much, because I'm almost never visiting Fandom as an anon. However, I don't remember Fandom ever saying they were going to honor a wiki's guidelines and policies. Did they say that in a blog or something?
Anyway, I suspect the wikis that have these crappy video ads are largely only top 100 WAM sites (maybe only top 50?), so you might want to start contacting admins from #1 on down and see what their users think or even just the admins. My main wiki is just outside the top 100, so I haven't seen this problem to complain about it.
I'm impressed that Jen Burton was the Fandom staff that commented. This means Fandom/Wikia was actually afraid. I still don't trust them to not continue to force it on wikis with less strong opposition, but it's a decent sign.
It doesn't surprise me that there is big pushback from game wikis, but it would be interesting to see the feedback from movie/TV wikis.
It looks like she was "Strategic Partnerships and Programming Manager" at Youtube which sounds like a primarily B-to-B role. It may actually serve to improve the quality of videos, but not in the short term. I don't know what it tells you, but it doesn't tell me much. At most, it might mean Fandom is doubling down on video ads.