You have a valid point. However this is pointing out ignorance of developers (I being one of them) that most of the time captcha is unnecessary and annoying to UX.
So yes, who would spam animoto? But you know what, now their spam filter is good enough, their user registration has been increased. Better more "foolproof" techniques will always be needed, and directed attacks are hard to prevent, but getting to a good enough point is great as well.
And the problem you face may be a smaller percentage of sites than animoto, who do need captcha especially if you are the target of a directed attack.
So yes, who would spam animoto? But you know what, now their spam filter is good enough, their user registration has been increased. Better more "foolproof" techniques will always be needed, and directed attacks are hard to prevent, but getting to a good enough point is great as well.
And the problem you face may be a smaller percentage of sites than animoto, who do need captcha especially if you are the target of a directed attack.