Why they would include a tablet oriented touch centric UI in a server product is a matter for another discussion...
The problem is that this a standard complaint everywhere, and that this is the standard response given everywhere.
In doing everything they could to force Metro down users' throats in Windows 8 (which is a decision I disagree with, but can understand), Microsoft completely failed when repeating that same judgement for a server OS.
Server-admins doing RDP does not want Metro. They have nothing to benefit from metro. They will never use metro. They will not install "apps" on their servers.
This decision has done nothing except harm Microsoft's perception among people who would normally be the proponents of their technology.
But Metro on Windows Server? It just warps my brain trying to justify that. I cannot think of a single technical reason for it to be there. Except maybe consolidation of shell code, and that's a crappy reason.
Like many in the industry I have a love/hate relationship with Microsoft, as many other companies.
This has to be a decision from the Marketing department on the engineering teams.