Also, the original article (original with regard the this HN thread, not the older article you linked to) talked about examining the tool marks. It's not just examining the large shape, it's about seeing the method of construction on a smaller scale.
Anyway, based on camel remains, it seems the splay-footed quadrupeds reached Arabia in the Holocene, at least 7,000 years ago. (Camels are believed to have reached ancient Israel only about 3,000 years ago.)
My imagination makes me think that it's a pretty obvious thing to do for any number of reasons and that there have been quite a few that have been lost to time.
Wonderful slice of some potter rivalry from long long ago ;)
A rule of thumb I've heard is that "ritual significance" is code for either "we have no idea" or "probably a sex toy", depending on context. In cases like this, I think the default assumption should be "probably art".
The article says they were thought to be 2000 years old but have recently been found to be 6000 years older than that. The second paragraph makes the new dating range explicit.
The article your read refers to 2,000 year old sculptures because it was written years before the research that added 6,000 years, not because they're different camels.
Unfortunately it's vague whether or not the different pictures are from different time periods, different sites, or what exactly.