Data is a toaster!
Sorry, had to. Anyways... on topic. There's a bit of difference between your comparison to the Landru machine and Data. He does have compassion and wisdom. He's quite possibly the most compassionate person on TNG. Wisdom? He can be naive at times, and remarkably perceptive at others. Is he perfect no? But those imperfections seem to me to be part of the human condition he's coveting.
As for a soul? I can't accept that as a criteria for sentience. If you can prove to me unequivocally that a human has a soul, then maybe I'll reconsider that. Until then I'd say it's just an abstract metaphysical term created by us to fill in the gaps between what we don't know and what we want to believe.
So is Data human? Obviously not. I do believe Louvois made the correct determination that while he's different he should have the freedom to find his own answers in it.