Sounds more like a war against unsupported drivers to me, but I guess that's not evil enough to be true for you.
Why is it unsupported? Pretty much all x86 base drivers work in Windows RT.. except Ethernet.
It's surely not an ARM restriction - there are ARM devices with Ethernet.
Android can use Ethernet adapters, and that thing is a pure mobile OS! Yet Windows RT, a subset of the full powered Windows, can't! You can't tell me it's because of technical issues (the fact that third party drivers work [which get taken down by MS?!] is proof that it's no technical issue).
Microsoft has deliberately crippled this feature on Windows RT on purpose. Reason? Forget my "conspiracy theories" if you want, but fact is that Ethernet is crippled on purpose, and Microsoft is putting effort to let it stay crippled. Why the heck is this the case? I am not saying that my explanation for Microsoft's motivation for this is perfect, but the issue exists nevertheless.