Can't speak for the OP but to me it's not a matter of using the format options (which can actually make the picture look worse depending on the situation). It's about why some networks choose to double and in some cases triple crop their SD feed instead of leaving it at 4:3 and calling it a day. I've noticed that the SD channels that use an uncropped 4:3 feed tend to look better. Just my 2 cents.
I'm not sure I follow you here. Double & triple crop?
Let me break down who is doing what:
The Military channel is moving to 16:9, which in the long run is a good thing.
It's still SD on DirecTV, so it's letterbox from Discovery.
On your receiver you can select formats that can add pillarbars, send the letterbox in 4:3 to the TV [original format], or crop [and zoom] the letterbox to fill a 16:9 screen.
The Military channel inserted old 4:3 footage into the letterbox, so they added pillarbars to keep the 16:9 format.
Now if your comment/complaint is what the picture looks like on a big screen, with a scaling factor of about 10:1, the scaler you're using [and how well it does this] has a lot to do with the end product.
SD will never look as good as HD.
I can "zoom" 16:9 SD with my Sony TV and it "doesn't look that bad", but this very much is YMMV.