No, I think you are right. Voldemort would probably not understand anything motivated by love. He only seems to understand fear, power, ambition and things like that. He mocks love several times in the book so I could definitely see him overlooking things done for love. This might even ruin his manipulations - yes, he could manipulate people through fear, but he might be surprised when it backfires on him due to love.
Hope that helps,
I agree with what Gina said about Voldemort mocking love in others. He's thinks it's for fools. But Tom Riddle is intelligent: I think he would know WHY Harry dug the grave (love for Dobby), but he would think Harry a misguided fool for doing it.