Did Walter "become" evil?

When watching Breaking Bad, which could also described as Walter Whites journey into darkness, one must wonder: are Walter's choices and decisions the by product of his life circumstances at the time of his cancer diagnosis? Off the bat anyone would be inclined to say yes, why wouldn't they But after seeing this quote in a web magazine review, I realized how on point the statement was. "The closer we get to the end, the more Walt scrabbles around and lashes out like a rat when it's surrounded, the less I'm buying Vince Gilligan's whole 'Mr. Chips to Scarface' quote as an analogy for Walt's transformation. That's the route the character has taken these five seasons, sure, in terms of his changing context. But I think the most horrifying part of Breaking Bad may be that Walt, at his core, didn't really transform at all. It wasn't greed or generosity or cancer or fear that fueled this reign of death and destruction. It was resentment. Seething, burning resentment, the kind that forms not due to poor treatment but due to an innate knowledge that you, the aggrieved, are better than said treatment, better than everyone who has somehow gotten the better of you over the years. ... Every moment Walt spent in front of a classroom he was thinking about how beneath him it all was. He was a genius; he was meant to be a millionaire, not this castrated cross between stepping stone and doormat. When you got down to it, Walt desperately wanted to teach every one ... a lesson, and I don't mean in the style of Mr. Chips." Instantly after reading this, it all became so true. Sure maybe Walt's actions were intensified when suddenly there became a date of expiration on his life, but in the reality of things, walter has been bitter a vengeful his own life, it only took one ride with the DEA on a lab bust to make him realize how to tell the world he was a force to be reckoned with.