There's obviously a good reason its on the front since every measurement states its a bad idea, otherwise. The two most likely reasons are either its cheaper or that there is insufficient room in the rear plate to accommodate it. Taking one apart would probably help answer the why. If I had to guess here it would be the latter since the back of the speaker is quite busy with the controls for the various filters and what not. The engineers obviously know its bad, so there is likely some design trade-off going on. Interestingly if you look at the back of the speaker its likely the ports extend all the way to the back from the IEC connector having to be offset upwards. I'm sure if they tried they could, but my experience as an engineer is that there is often a reason for doing things that appear less than optimal. It could even be down to aesthetics, but I think they look better sans port in the front.
Edit: The front baffle is actually all one piece, so I would not rule out cost-savings or DFM. If its all plastic, that would make sense to put them up front since you can just mold it all in one go, and then the speaker is only three modules to assemble (case, enclosure, and amp). Oddly on this model vs. the one on their website they are separate inserts, so I wonder if Amir was sent a prototype?