I don't advocate getting into a battle of wills with your faculty committee; it makes the process much more difficult. But at the same time, it's important to be able to adhere to your own sense of purpose, and your own sense of what the project ought to be.
This is one of the most difficult pieces of the dissertation project to manage: how much of your vision are you willing to sacrifice to the demands or suggestions of your committee? How much do you want to respond to instructions of your committee when they call on you to do work that you would not have done?
The answer, of course, is not simple. It's always a matter of judgment calls. First off, is that comment that says "include a discussion of X" or the one that says "cut out section Y"--are those comments demands or suggestions? You have to judge with respect to your committee. But I think it is easy for a graduate student to forget that sometimes professors ask questions or make suggestions because they want to help.
I remember clearly being stopped part way through my qualifying orals. I don't remember exactly what the subject was, and I'm not quite sure which professor it was who spoke first, but she said to me something like "We're asking the question because we're trying to help you plan your dissertation, not because we're trying to find out a weakness." So one thing to ask yourself when looking at those comments is, are they demands or suggestions?
The next thing to do is to examine whether or not that comment really helps. And to do this, you have to have a good idea of what you're trying to accomplish with your dissertation, because without such a sense of purpose, how can you determine whether the comment helps or not? It is crucial to put aside any resentment at being ordered around, and just examine the suggestion on its own merits: if the suggestion helps you--and I emphasize 'you'--that doesn't mean that you'll be able to recognize its value immediately; you have to give the idea at least a little chance--though only within the crucible of your scholarly analysis. Some suggestions really do help. If you can see that a suggestion helps, then you want to use it.
Some suggestions don't really help. These ones you need to figure out how to manage. One good tactic is to simply ignore them. If you turn in a completely revised draft that's significantly different from the previous one; if that draft incorporates some of the suggestions that your professor made; and if that draft is focused, coherent and generally complete in its structure, then it is quite possible that your professor will evaluate that draft on its own merits, and not on the basis of comments written some months earlier.
Another possible strategy is to use the handy "that is outside the scope of this discussion." I was talking today with a Berkeley Professor of education who was telling me how he had shown a draft to a friend, how that friend had taken him to task on a certain issue, and how he had decided to respond by putting in a footnote that acknowledged the difficulty and said "but that is outside the scope of this discussion." As he said to me: one does not wish to appear ignorant of the subject, or the issue, but opening the discussion is like opening Pandora's box: all sorts of problems come out. His "Pandora's box" is parallel to the rabbit holes that I was talking about. But he's right, in a way: going into that discussion actually does create many problems, and given the desire for concise and focused work, even exploration of interesting subjects is something of a problem. We may be able to convincingly respond to a suggestion by writing a paragraph that acknowledges a body of material that is relevant, but is outside the scope of the study.
It's possible that the suggestions I have made above can help resolve the great majority of problems with comments and suggestions from your committee that you find difficult. It seems to me likely that this strategy, repeated over a couple of cycles of feedback and revision, might be successful in avoiding direct conflict. If you are able to respond positively to some of the suggestions, that always helps defuse difficulties related to failing to respond to all of the comments.