The counterargument is that suppressing truth and speech is indecent, regardless of intent. That is, the lesser wrong is still wrong. Boiling people down to utilitarian guesswork is part of the problem. It is fair to point out that the alleged decency is premised on skipping past established ethical and moral frameworks.
So let's avoid arguing over the definition of "decent" by being more specific. I claim:
It's possible for someone to endorse the position taken by Google management on this even though that person is highly intelligent, is far from indifferent to others' suffering and oppression, and habitually goes out of their way to treat others well, including others who are unlike them and far away.
I do, of course, agree that if you get to define what "decent" means then you can make it so that no decent person disagrees with you. In this case, I think that requires a definition that has built into it either an answer to the specific object-level question at hand, or else a specific position on a subtle philosophical question (consequentialism versus deontology versus virtue ethics versus whatever else) on which smart people who spend their whole lives thinking about this stuff are far from all agreeing.
This is (as I understand it) a deontological, rather than a consequential, argument. So that cannot really be a 'counterargument' because it has a disjoint set of premises. You can argue that the premise for GP's argument (something along the lines of `The decision of whether to operate Google in China should depend on the aforementioned having better outcomes for chinese citizens than otherwise`) is incorrect or you can argue on the basis of his premise, but giving a different argument on a different premise (something like `the rule "don't censor political speech" should never be broken`) does not make a counterargument.