I suppose it depends on how you define "being human." Is it biological? Is it a mental state of being?
At the core Data is an android programed to emulate humans, or at least the best examples thereof. It's what he is and it's his primary function.
Data's character evolution would argue towards the later definition, that striving to be more and better than he currently is, is what defines his humanity. Then again by that definition it really is fundamentally racist. By it's very name it implies that only humans are capable of being more than they are. Somewhat surprising that the only time the Federation gets called on this is during STVI.