They are limiting the spread until it has been fact checked. I can see the rationale behind that, too many people are unfortunately incapable of critically analyzing a piece of information. By the time the facts are out, the damage has been done and it can no longer be reversed. Now on the other hand the damage can still happen, after the info has been verified. But nothing wrong with being vigilant since I agree that there is potential for misuse.

Not being able to send certain links in Facebook messages is nothing new by the way, it has happened to me a few times with links that were definitely not virus links. I can't remember the contents of the links though.