Worship is not always complete love and adoration. I'm pretty sure few Aztecs had a soft spot for the god who demanded the blood of thousands. And doesn't Islam translate to something like 'obedience.' Awe should be sufficient, for most of the Princes.
Ah Islam means "submission" moreover, as it's used in the willing sense of the term, as in, not enforced. (Whether than translates into real life, whatever.)
And I'm pretty sure the people who were sacrificed in Aztec times volunteered themselves freely, and did so out of adoration for their gods and the immense honor it was in that society. I do know that it wasn't at all along the lines of the (cringeworthy) "red-drink" sacrifice seen in Oblivion.