Google's the one making the claim that publishers should do the work and not benefit from doing that work, so why can't I benefit from Google's efforts as well?
If I have a book in my house and you want to cite text from it, you can't cite Fair Use to break into my house and look at it.
If I did, though, you'd charge me with breaking in, not with stealing.
Google's not claiming you don't have a right to reuse the text. They're placing restrictions on how you use their service to access that information. It's no more a copyright claim than your local library telling you that you have to come during their operating hours.
Maybe Comcast only works from 9-5 anyway. It's their service. It'd be like a highway charging you different amounts depending on what time of day you traveled.
I'm not quite sure what the parallel's are to Google Books though... (I think we've gone too far down the metaphor rabbit hole)
Google's (and other Internet services providers) terms of service restricting your usage aren't anti-competitive in nature. The restrictions they're placing on your usage of the content don't prevent you from getting that same content from another provider (especially when we're talking about public domain or fair use text.)
Carriers are regulated much more heavily than other businesses, because the nature of their business creates a disproportionate number of opportunities for anti-competitive practices and other shenanigans. Also, many of them have a monopoly or duopoly position in their marketplace, and as such are scrutinized more closely for anti-competitive practices.
Example: As a monopoly cable provider I can be the dominant internet provider in your city. So to extract more money from users, I create a new subsidiary owned by the same (unregulated) parent company as the cable division that charges for online video. The parent company then tells the cable company to throttle the bandwidth for all competitors so that everyone is forced to move to that new company's video service, regardless of whether it's actually a better product. This is anti-competitive and harmful to the public - rather than offering a better service, I'm using my ownership of one business to unfairly hamper free competition in another market.