Good observation and a great question Conrad.
In the design phase, we struggled with the decision for a long time, as are well aware of the code and benefits of having the male end facing downwind.
Our decision was based on these factors in no specific order:
The damper is easy to open all the way with a paperclip-like wire hook, and access the duct for removal of any buildup at the collar edge.
Retro fitting was critical in our target market, and we felt the existing duct penetrating the wall would be foamed or caulked in place and be difficult to remove and then replace, or to remove the caulk and foam that would typically be an obstacle for getting a collar to slide over.
Make the collar fit with minimal tolerances to minimize any chance of buildup.
I know it is not correct, but in retrospect, I believe it is still the best decision. The current hooded dampers that are on many homes, are such energy wasters. Retrofitting this vent to replace those legacy hooded vents saves the homeowner energy costs as well as tumbling the clothes less.
More information and specifications at
www.dryerwallvent.com Thanks