Mojang is _very clearly_ trying to use the name Scrolls to promote it's own product.
Pardon my ignorance, but it apparently is "very clear", and I missed it: your conclusion is based on what evidence of trademark infringement? (Zenimax is not claiming copyright infringement.)
If Mojang had chosen "Scrolls Of Elders" or "The Elderberry Scrolls" (with berry in a small font), and if the game's overall mark was closely similar, then maybe we'd have a real case of trademark infringement.
Anyways, apart from the confusion of trademark and copyright, you state copyright law prevents humanity's progress, but Zenimax should sue the socks off Mojang? I'm confused.
Quite honestly, I appears Mojang/Notch are quite good at stealing ideas and turning them into \\$\\$\\$.
The Elder Scrolls series isn't even really the same type of game as Scrolls, from the limited leaked info. If anything, some like Wizards Of the Coast would have the copyright (but not trademark) case, since Scrolls looks to be an online card game with RPGish flavor.
As for the idea of "stealing" in general, you can reduce any game to simple statements such that they look like "copies" of others. Limbo? Just a platformer like Mario. Nintendo should sue Playdead, I guess.
I say kudos to Mojang for executing so well off a re-retread of some card/RPG ideas! We, as game devs, should learn from it all.
One negative takeaway: while it might be great PR for Mojang playing the underdog, it doesn't make business sense to fight and burn up your legal funds on an unreleased game's title.