It's getting weird now: Why do so many tech billionaires want governments worldwide to give away money for free?

Tech magnates Elon Musk and Mark Zuckerberg have already called for "universal basic income," a government program that would give all citizens a set amount of taxpayer money, regardless of whether they have jobs. The handouts would come with no strings attached, just free money.

Now, Stewart Butterfield, the CEO and co-founder of the workplace chat program Slack and also co-founded Flickr, is joining the call.

Other billionaires agree, like Y Combinator President Sam Altman and eBay Founder Pierre Omidyar.

Zuckerberg famously launched Facebook from his Harvard University dorm room in 2004. And Musk, at just 24, created an Internet "city guide" for newspapers — which he sold a few years later for $300 million.

On July 4, Zuckerberg took to Facebook to recount a recent trip to Alaska — and how a state program for residents works. The post praised Alaska's Permanent Dividend Fund, a $52-billion pile of cash from oil revenues that the state government doles out to citizens each year, usually $1,000 to $2,000 at a time.

"This is a novel approach to basic income in a few ways," Zuckerberg wrote. "First, it's funded by natural resources rather than raising taxes. Second, it comes from conservative principles of smaller government, rather than progressive principles of a larger safety net. This shows basic income is a bipartisan idea."

That approach is one that "may be a lesson for the rest of the country," he wrote.

The benefits of such a system are twofold, he wrote.

"First, a common issue with safety net programs is stigma for participating, but here everyone we met was proud of this — both for its cultural heritage and for the individual accomplishment of catching and preparing their salmon. Second, most effective safety net programs create an incentive or need to work rather than just giving a handout."

Musk, who moved on to Tesla and SpaceX after selling his internet company, also thinks people will need a universal basic income to survive in the future.

"I think we'll end up doing universal basic income," Musk told a crowd at the World Government Summit in Dubai in February. "It's going to be necessary" because of automation, which will replace millions of workers over the next 30 years.

"There will be fewer and fewer jobs that a robot cannot do better," he said. "I want to be clear. These are not things I wish will happen; these are things I think probably will happen."

Altman agreed, writing in January: "I'm fairly confident that at some point in the future, as technology continues to eliminate traditional jobs and massive new wealth gets created, we're going to see some version of [UBI] at a national scale."