Personally, I think Twitter (or any social media) gives the impression that this group is more radical than they probably are as a whole.
Bush, Clinton, Bush and Obama were not radically divergent from each other politically and socially. Where social policy diverged, it was obviously electoral, not personal. Every single one of these candidates would have/did support stuff like “strong” borders or DOMA until they didnt in practice or somber reflection.
We have a populist rebellion against the status quo and educated youts aren’t Ayn Rand, Goldwater or Milton Friedman fans anymore.
One thing that I was wondering about related to this, which might be a slightly more concrete question and easier to talk about:
In 1996 Paulina Borsook wrote an essay which she later expanded into her 2000 book Cyberselfish, in which she argued that Silicon Valley was super-libertarian in a way that she strongly disliked.
There are still people on the left who feel that Silicon Valley as a whole is disagreeably indifferent to income inequality and class issues. (This is sort of like Thomas Frank's complaints: you worry about culture war topics, but you should worry about income inequality instead.) But I doubt many of them would see Silicon Valley as libertarian in anything like the way that Borsook experienced it. Nor do libertarians or conservatives, many of whom say it's now become uncomfortable or risky for their careers to express their views in Silicon Valley.
How did we get from a 2000 Silicon Valley in which someone is writing a book like Borsook's to now?
Edit: actually, an even more famous example of roughly the same idea is Barbrook (as opposed to Borsook) on "The Californian Ideology"
https://en.wikipedia.org/wiki/The_Californian_Ideology
which is from 1995.
It's not.
Big wage-labor-dependent investor-owned companies and leftism aren't particularly compatible.
Non-economic-class identity politics, a bourgeois distraction from leftism, are popular at many big tech companies, because they provide a veneer of progressivie image without seriously challenging, and in fact deflecting the most serious challenges to, the capitalist economic order.
Now, from the perspective of the far right this looks kinda like leftism since it's somewhere off to the left of the far right, and US political dialogue is shaped by the far right doing a very good job of shaping the media by working the refs over a period of decades.
There are minor reasons too. One is that many tech workers are young people fresh from university indoctrination, but without children and mortgages. Another is that many tech workers come from outside the USA. Besides that fact that many non-USA places are more leftist, there is a selection bias caused by the fact that these people are not dedicated to staying in their own countries; they are fundamentally more globalist than the people that they leave behind.
While I agree with the statement about selection bias of immigrants, I have to take issue with this part of your claim. The countries most relevant to tech companies (India and China) are very nearly (or entirely, depending on your standards) ethno-nationalist. India is currently trying for demographic change in Kashmir [1], and I won't waste your time repeating the plentiful coverage of China's efforts to maintain their 91.6% Han majority.
Socialism is central to modern software development. If it was not then there would be no "free software foundation", "no open source", no plethora of "copy-left" licencing. I don't say this as if it is a bad thing. Clearly we are centuries of person years ahead software wise as a result of this socialism.
This individual behavior stands in stark contrast to the behavior of most tech companies as a whole that are clearly not "leftist". There is nothing leftist about NDA agreements, confiscation of IP and anti-poaching agreements to control wages. There is nothing leftist about dark ui patterns, shifting terms of service and harvesting of personal information and micro-transactions.
Many people will complain about working conditions of people with lower skill level, most of them are not going to quit over that and renounce the fat faang-style paycheck.
Same for massive surveillance, pervasive tracking, and unionisation and many more topics.
Anecdotally: I've seen a few people turning their eyes the other way as soon as Amazon or Google started dropping monthly cash bombs on them.
So the question could actually be: what is the actually predominant ideology in big tech companies?
As I mentioned in another comment, some Silicon Valley leftists are not that interested in income inequality and are more interested in culture war stuff. In that case they're already not hypocritical for making a lot of money, even if other parts of the left think their priorities are misplaced.
On the other hand, people who are especially concerned about income inequality might think that their preferred way to address it is by having the government increase the minimum wage and/or expand the welfare state. In that case they might be perfectly happy to earn a high income themselves while also trying to support politicians who want to do these things (say, like Bernie Sanders).
This has also come up when critics of redistributive policies ask why proponents don't simply donate more of their own money to the government, to which the proponents will say that their priority is to change public policy (which might scale better than relying on individual decisionmaking).
Related:
https://en.wikipedia.org/wiki/Prefigurative_politics
In my view, people who don't prioritize or practice prefigurative politics aren't necessarily hypocritical.
Techies are wage slaves as much as anyone else. They just have a higher scale of cost and income.
Consider this: http://exple.tive.org/blarg/2020/08/31/consequences-of-code/
One line is significant: "three errors are an operational mistake, four hundreds are a company policy".
The point is simple: if your employer is doing unethical stuff then you are affiliated and related, sometimes responsible too, for such things.
Either you quit or at least have the decency to say "yeah it's wrong and everything but I get a fat paycheck every month and that settles it for me".