Facebook blocking iOS devices from Chat?

As some people are aware of, Facebook doesn't have an official iPad app because Mark Zuckerberg doesn't think it's needed. Which means there are only two solutions, either use the Facebook website via iPad, or use one of the 3rd-party Facebook apps (which in my opinion, all have horrible user interfaces).

The problem with using the Facebook website on your iPad, is that you can't chat!  Pictured below is Facebook via both the default Safari and Atomic Web Browser (99¢ in iTunes App Store).

However, one of the great things about Atomic, is that you can change the User Agent (identify it as a different browser). When I change the UA in Atomic to identify it as a Desktop browser, rather than an iPad browser, you see pictured below that Chat on Facebook does indeed work.

This proves that the lack on Facebook Chat on the iPad is not a limitation of the device, it is Facebook blocking access from the device itself. What is confusing, is that if Mr. Zuckerberg is going to block access, why not make an official iPad app?