The word Easter can be derived from Oster, the old Teutonic form of auferstehen/erstehen meaning resurrection.
Easter isn't called Easter in German, it's called Oster. Oster and Osterland in German mean "eastern" and are associated with the East, land of the rising sun, spring, all that renewal of life stuff.
I've never heard of it being associated with auferstehen, and I am a bit surprised that the old Teutonic form of auferstehen is relevant, given that the Bible only got translated into German by Luther, somewhat after people stopped speaking Old Teutonic. I do think the other derivation from ?astre or ?ostre in English is much more widely accepted as true.
I am very happy to recognise that for many Christians, the festivities are about the birth of Christ. But the name is not a good argument to support this. It's only "called Christmas" if you speak English.
If you were born further South (in Europe) you'd be calling it "birthday", ie, variants on Noel, Natale, Navidad. So yes, that's a Christian reference, widely shared across Catholic countries. And Germans say Weihnacht(en) which is "holy night".
But further North- Denmark, Sweden, Norway- and you'd be saying Yule (Jul). We called it Geol before we called it Christmas. It's pretty accepted that Yule and variants reflect the old, pre-Christian festivals in the Nordic countries. So if we were having this exact discussion on Nordic Mumsnet, you'd have to concede that the name of Yule reflected the previous faith associated with the holiday, and not the current one.