I wouldn't agree with that at all. Zealots were religious devotees who felt that Jerusalem belonged to a single ethnicity by divine right, and were more interested in self rule. The Sixth House, however, is traditionally secular, and towards the end of the main quest has expansionist goals. The zealots simply wanted self rule, the Sixth House wants expansion.
Secular?!? House Dagoth was the most pious of the houses, and now they have built their own faith on the back of a dead god, and in Akulakhan they were attempting to create yet another.
It's a fanatical cult entirely centered on one deity and its ranks are filled by the most traditional, xenophobic and conservative of the Dunmer. Dagoth Ur may want to rule the world, but he knows nothing of the world. He has spent three thousand years in one room, obsessed with a few royal councilors. It seems strange to want expansion when Vvardenfell is a world in and of itself. It is in fact the very heart of the world, with its own gods and the most insular culture and climate anywhere. Ken Rolston may have just added in that line of dialog to raise the stakes.
Zealots were religious devotees who felt that Jerusalem belonged to a single ethnicity by divine right, and were more interested in self rule.
That is an excellent way to describe the Sixth House and the more conservative Dunmer. I don't know about the Zealots, though. I usually hate playing the comparison game.