Why does Silicon Valley lean left politically?

It doesn’t. It is just that the movers and shakers of Silicon Valley cannot find any other party sane enough so they end up supporting the Democrats.

Do you seriously think that Silicon Valley with its Venture Capitalists and its entrepreneurs and its LARGE flock of engineers and product managers and MBAs who dream of starting their own companies and going public and making 100s of millions are left-leaning?

The right-leaning party - the Republicans - cannot stop ranting about family values, venting hatred at homosexuals and screaming about Sharia and that is why the Silicon Valley BILLIONAIRES end up supporting the Democrats.

Silicon Valley only leans left in American thinking.

The powers that be in the region like taxes to be as low as possible, want minimal government regulation, want speech as unfettered as possible, and support barrier free or at least reduced trade.

What keeps them out of the GOP is they also believe that in matters personal, your business is your business. If you don’t conform to gender and sex norms that’s a big so what because your business is your business. Silicon Valley does not just need an educated workforce (and they really have to have an educated workforce), they also need an educated customer base.

Like all capitalists, they also need customers. There are two models prevalent, people pay for your goods and services, or the sellers of goods and services pay to have access to potential buyers. There is genuine fear among many in Silicon Valley that their innovations designed to get people to pay for software and hardware to replace workers will increase unemployment and reduce the potential base of people to buy goods and services. You cannot make money selling goods and services to people who cannot afford to buy them and you cannot make money offering access to people who cannot afford what is offered.

In most of the rest of the nations with large economies the powers of Silicon Valley would be right or center-right. In the US having to choose between imperfect options, they lean to the US left.

HIPPIES

LBGTs

SCIENTISTS

IMMIGRANTS

Living in cities means living closely together with other people from a variety of different backgrounds. Conservatives by their nature (is in the name!) are conservative with respect to who they want to associate with and what they want to learn; they also don't prefer the social services and rules needed to support higher densities. Cities are then filled with liberals as the conservatives self select themselves away from them.

Can you name one period of times where technological advancement was led by conservatives and reactionries? Nope, again, it doesn't fit into the definition of conservative! Instead, progressives and “free thinkers” have always been the ones to drive for societal change, while conservatives prefer more stability and less change (again, the meaning of “conserve”). Don't get me wrong, there have been points in history where the conservatives come out looking better rather than party poopers, usually where radical change has occurred in a bad way (e.g. Bolshevik Revolution). It also lines up with the adage that older people tend to be more conservative (they are more tired of change), though this is mostly a myth.

So the answer is that leftist politics drive change, innovation, and invention as a matter of definition. Silicon Valley is all about this, so we wouldn't expect it to lean right politically.

Education does that to you. It allows you to have critical thinking, deep analysis.

We realize that we aren’t perfect. Each of us is different. Some are more different than others. If we want others to tolerate us, then we’d better tolerate others.

We realize that for thousands of years we didn’t have social programs and we didn’t uplift anybody while just the last 60–70 years or so we have uplifted so many people out of poverty. The majority of Europe and the US are above the poverty line now. Social programs work. Helping each other works. Sure, there are abusers, but the budget of all social programs combined is not even a fraction of the defense budget.

The right keeps screaming “Not my tax money” but they aren’t getting it back. It just goes elsewhere not helping them. Every man for himself doesn’t work for most Americans. In this society, money makes money. The tough part is how to help those who don’t have money to make money. Just put all the money into the defense doesn’t help unskilled, uneducated Americans make money. These people won’t get to keep their tax money and won’t gain any money from anywhere else either.

So Silicon Valley leans left because it knows left policies work. That’s how most of them get there.