I tend to stay out of the forums on most sites because debates usually go
ballistic after awhile... :o)
No nude thumbnails in the galleries will not  mean that it is the end of all life
on Earth.
3D Commune and PoserPros have had a no nude thumbnails policy for awhile.
I suppose Daz does as well, but I don't post there and it doesn't matter to me anyway.
To me the no more thumbnai policy makes no difference as I never posted nude thumbnails
in the first place because I rarely make a nude render.
I don't have anything against nudity or people who render nude images.

When we upload images, we have to tag them with an advisory if the image warrants
such an advisory.
I personally don't think thumbnails need to show bare asses,  areolas and nipples.  
If it's flagged as nudity and /or violence one would assume that is what the image is about.
Some may see this as a form of censorship, but it seems to be more of a standard
thing as far as gallery posts are concerned on other sites.
Also, from the administration perspective, their case about the nude thumbnails and their
online publications would be seen as a problem that could be easily overcome by
not allowing any more nude thumbnails.
I had an image temporarily suspended yesterday due to a thumbnail issue.  I found it
a tad unusual, but I sent another one that was acceptable and moved on.
(I made the deleted thumbnail my avatar)

I am a very, very, very bad man . . . :o)

That was  my 2 cents Canadian and I'm not looking to debate the issue. :o)