Timboli: Is 'Skirmish Mode' something where you needed to connect with other players? If so, then that is a form of Multiplayer, and GOG have never to my knowledge promised that the MP aspect of a game is guaranteed to be DRM-Free. (...)
There are many games here at GOG, where the MP aspect is DRM. How is DOW2 any different to those? It's not like it doesn't have a great SP aspect.
It seems to me, that DOW2 has a lot of SP content DRM-Free ... which meets the guarantee brief from GOG.
It is disappointing that DOW 2 doesn't have LAN mode, but so many games are like that these days. (...)
Maybe it's a matter of terminology? For me, "skirmish" is not inherently tied to "multiplayer". Instead, it contrasts with "campaign game". A skirmish game is a short battle on a fair (mostly symmetric) playing field.
Yes, the implementation of this playing mode is often (but not always) tied to multiplayer. I.e. the question is only whether humans or AI-bots take the player slots.
In the case of DoW2, the main problem is the removal of LAN play, which it once had! With it came the technical capability to "host" your own skirmish games, regardless of whether other human players joined or not.
There are other games sold on GOG, such as
Supreme Commander, which still allow for LAN play (and thus offline bot matches). I fear the day when GOG proudly announces the Galaxification of those last survivors...