In Crisis of Conscience, Ray Franz expressed the opinion that they really believe it
For starters, the "Governing Body" is not one person. It is a group of people that has changed hands over time as individuals of the group die off and are replaced. Would you speak of the U.S. Supreme Court as if it were one entity? I think any time one generalizes about any group of people, they are either over simplifying or conflating.
That said, if the question was "do you think individual members of the governing body are villains or are they simply deluded?" then I could give my opinion on that.
Back in the early 1980's when I was at Bethel, I knew one member of the Governing Body very, very well. I actually did field service with him pretty much every week, often actually working with him one on one in field service. He was one of the few single GB members, so he did not have a wife to work in service with and that left us single guys able to rotate our field service with him. We often had lunch and/or dinner with him, and even attended congregation gatherings with him. I rode in a car to the meetings with him 3 times a week. I witnessed his sense of humor first hand, and could feel his earnestness in his prayers and the way he behaved in pretty much everything he did. This man was ALL ABOUT Jehovah, the Kingdom, Jesus Christ's return and every trivia point that the Bible had to offer. His mind was on these things all the time, so much so that even for a Bethelite, it seemed not human. Yet, there he was, all with a decent sense of humor (I teased him and others around me all the time and he laughed or smiled in most of the shenanigans I did) and was a kind and gentle person most of the time. I think I saw him cranky once or twice, but if there ever was a person who could be said to be "like Jesus" it was this man.
I recall one day we were approaching people in the subway to talk to them in field service and a man was at the magazine stand looking at the pornography side of the stand. As Bethelites, we always knew which side of the stands NOT to stand next to because that is were all the nakedness was on full display. Back then in those years it was not hidden much. Anyway, this GB member walked over to the man studying which girlie magazine he wanted to purchase and stood next to him while the man looked over the offerings. I stayed back, fearful of being seen next to the nude pictures. This GB member watched the man for awhile and the man finally noticed this little Yoda looking gentleman smiling at him. When the GB finally had the man's attention, he said to him "Why are you looking at all these naked girls? This is not what is going to make you happy. You need to feed your mind on spiritual things. Let me share this scripture with you..."
I met other GB members as well. I did not know them as well as the one I just described, but I saw them also quite frequently and witnessed their personalities. Some were nice, others were jerks. Some were full of themselves and others were relatively humble. Fred Franz was by then a nearly blind shell of what he probably used to be at one time, but it struck me how simply he was dressed and how little ANY of the GB actually owned for having toiled away most of the adult lives as the leaders of a large religion. Had they been executives of even a small company for that long of time, they would be quite well off. Most of the GB I knew of had little, all packed into a simple room. Granted, it was a room bigger than mine was, but still, nothing compared to what an exec of a large company would have.
My opinion: Most of the GB actually believe what they dole out. Perhaps there is one or two who know they are dealing out a bunch of crap and do their thing for power, prestige or whatever else. But I believe most have drank the Cool Aid and are serving it out to others. I think most are in a state of denial about the horrors they inflict on others, telling themselves that it is what God wants.
I say this because I have witnessed what many are like first hand and not because I want to make excuses for what they do.
That said, my experience was nearly 40 years ago, so I admit I do not know any of the new generation of GB. Perhaps they are different than those I got to know all those years ago and they are now all purposeful villains.
But I doubt it.