All these SV companies hire based on ability. They are many things, but stupid is not one of them. The best people will be kept on the key projects. Those hired for “diversity” reasons will be put in places that best suit their ability, but that maximize the PR impact and minimize the damage they can cause.
What you say suggests there is no test for political attitudes and that's generally true, but nevertheless the customer-facing and decision-making people are overwhelmingly progressive/liberal.
You will find conservative attitudes pretty much only among the SW architects, systems analysts and coders and other engineering roles. The "creative", product management, sales and senior management staff tends to be young, very "socially conscious", and buys in to all the diversity and SJW groupthink. Most of the companies have the same structure, so they compete for ability within these categories, but the attitudes of the non-hard-tech category are super left wing wherever you go.
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Much of the “diversity” at Google is (homo)sexual, and the freaks are kept around to please the freaks at the top.
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