Voldemort was malicious and power hungry. He never felt/received an iota of love, ever. The divide between the muggles and wizards was created in him because of his father's actions. Realizing what his mother was, his father had left her. And when Riddle found out about this, I think he realized that muggles and wizards could not coexist in society as it was. One had to dominate the other. He being a wizard, obviously chose dominion of wizard kind over muggle kind.

Thinking about it now, in reality a secret society as large as the wizarding population is made out to be, cannot live in secrecy for long. Much like the X-men factor. A portion of each race would try to undermine the other, if not obliterate. If this story that JKR started was brought to an ultimate conclusion, I am quite certain that it would end in a major catastrophic war between muggles and wizards. And I believe that the muggles would strike first, considering our own insecurity, specially since the wizards seem to be so reluctant to do so.