He thought about the universe in terms of how it would be logical for a creator to construct it. I think he felt that this helped him to think about the subject matter objectively. "God does not play dice" was intended as a rejection of quantum physics. He was a stubborn, hard-headed, arrogant schmuck, and the only reason everyone didn't hate him was that he also happened to be a scientific genius. In fact, a lot of people hated him anyway, and he was widely considered an idiot in some circles. He's classic HFA, and he probably had some other developmental quirks as a bonus.
My grandfather was an engineer for Carolina Power & Light for most of his days, and he fits a similar bill. He had such trouble with speech growing up that his mother made him learn Latin as an attempt to assist him in this area, and he was generally strange altogether. He would hardly speak to me unless I could get him started telling war stories or chatting about some intellectual subject or other, and then he really hated any attempts at give and take conversation. When I got older, he wouldn't talk to me much at all, and he generally felt uncomfortable around me. As he started taking a colder stance toward me, however, he continued having a good relationship with my younger brother in spite of there being a greater intellectual rift between them than with me.
The fellow who programmed the software for the Patriot Missile was HFA as well, which I know through a friend who happens to be dating his ex. The cause for the break-up? The dude insisted upon pushing her buttons incessantly to see how she worked, and it had begun to make her insane. The kid from the previous marriage happens to be HFA as well, and the friend in question once quizzed me a bit on the issue.
Yes, people of scientific genius and engineering skill do have a higher propensity than most for being HFA. This should not necessarily be seen as an encouragement, for these people are really exceptional in a lot of ways. In fact, being extremely intelligent in one area doesn't necessarily mean that they are apt to fully understand other realms of thought. I don't think that Einstein's views on religion should be considered of terribly high importance because this subject is well outside his area of authority. Einstein should be appreciated for what he was, and there I draw the line. He is not the person I would go to if I had a question about religion or spirituality. If I wanted a lecture on General Relativity, I'd talk to him.
I find it unfathomable that people can knowingly subject themselves to beliefs which they know to be implausible, and I know from experience that attempting to do so myself would eventually lead me to insanity. However, this doesn't necessarily mean that I have higher powers of reasoning than others or that I have a less spiritual personality. All it means is that religion conflicts with how I think. Ultimately, I am confident that my views on religion are the right ones, but I acknowledge that my core reason for holding them is that it just happened to rub me the wrong way. Perhaps a religious person would sneer at me angrily and say "it's called faith, you ret*d. Most people understand this concept by the time they're seven years old." Let them.
The same goes for Einstein. If you want, you can read about his reasoning on the subject and see if it works for you. However, being a scientific genius just doesn't give him authority on this subject. In fact, I'm seriously against the concept of holding up scientific geniuses who happened to be atheists for this very reason. For most people, religion is not about logic or empirical reasoning. It's about morality and meaningful existence, and I think that any argumentation against religion should be left up to people more suited to thinking and talking about such areas of thought.