Its a real shame. These pictures are intended to be shared throughout the internet.
That's true. Furthermore, as a form of parody, they are most likely protected by US free speech laws, though I don't know what that means for members in other countries. But that's not really the issue, here.
This is a private forum and the owner(s) has, for whatever reasons, decided he/she doesn't want members embedding images to which they do not hold exclusive copyright or permission. It's simply an arbitrary rule; the rationale is irrelevant, however sound or unreasonable it might appear. As members we are obliged to abide by these rules. This isn't a democracy.
It's like being invited to someone's home for dinner and being told to keep your shoes on. Many of us would find this silly and uncomfortable and even against our cultural norms, but what choice do we have in the matter if it's not our home and not a public space? I know, that's a weird analogy - lol.
On the other hand, I think there is a social phenomenon here that transcends the it's-simply-a-private-forum model. I think at some point a forum like this becomes more than simply a collection of guests. I hate the word "community" for a variety of reasons I won't bother discussing here, but I think that, after some time, a forum such as TPF becomes a community of sorts. And, as a community, I think some limited democratic governance can be a good thing. Of course, there's no obligation for the owner to indulge the membership's opinions, but I think it ultimately makes for a friendlier and happier atmosphere to allow some input from time to time.
Anyway, that's how this peace and love California girl sees it.