Is it just marketing for foreign or public use sales v military?

From what I understand is they make'm over in Poland so they can sell them as civilian.

The UH-60M and S-70i are basically the same helicopter ..... basically.  They have the same fuselage, drive system, and engines.  From there the US Army gets some things that aren't shall we say available on the "open market."  The UH-60M is built in the US and the S-70i in Poland.  The other major difference is that the aircraft built in Poland are not built under a FAA Production Certificate and as such are not eligible for registration on the "civil" register in the US.  Now LA County, Cal-Fire, Colorado, San Diego Fire, etc. are flying them yes but they are under "Public Use" rules.  

There's now a S-70M which is restricted category.

The S-70M is a "paper" helicopter.  Go read TCDS H5NE specifically note 19.  Pretty clear that this is something that Sikorsky is trying to sell but has never actually built and there is a pretty long list of items that must be completed prior to them ever entering servivce.

Uh-60 is manufactured for the military and the TC is issued under FAR 21.25(a)(2). The S70i is a civilian aircraft manufactured by Sikorsky under FAR 21.25(a)(1).

Generally need armor plating around crew and engines. They don't generally need self sealing fuel tanks, among other battle hardened systems.

One difference is price.  If you can afford a S70i, you're a goverment employee paying way too much for a Blackhawk with tax payers money.  :-)

Sultan of Brunei donated his S70 to FSI WPB Fl years ago for Mx training 

Note the "cargo" door.  A true Sultan of Burnei S70 in the USA...

UH-60 is a Military Ship.