Because Google is not a publisher, and selectively choosing how to present information according to the predominant internal politics is unethical without a disclaimer, which currently does not exist, given Google's status as the defacto gateway to information on the internet.

Curating information in such a manner is, ironically, marginalizing the groups who's views are being suppressed. Information should flow freely for people to make their own decisions. This is a dangerous amount of power for an increasingly biased private entity, particularly given certain choice quotes in this article and others regarding googlers' views on the current presidency.