So he basically called you snobbish, "superior-minded", bigoted, eternally unhappy, drugged up, foul-mouthed,and belligerent. But he was nice and gave you the opportunity to pick one. That's funny as hell; your letter must have really pissed him off.
That said, if I owned Taco Bell (or was the CEO), I'd fire that fucker. His job title, CEFRNS stands for "Chief Evangelist For Really Neat Stuff" which is what the head of the networking and engineering groups are sometimes called; the regular job title is "CIO, Chief Information Officer". So the letter didn't even get passed to the complaints department; the networking folks passed it up to him. He shouldn't even be answering complaints, let alone answering them in a cocky and insulting manner no matter how abusive the letter he got was.