Bernie Sanders has long been hostile to people who make lots of money, whether they work in tech, banking or energy. And he hasn’t spared real estate developers from the animus. For decades he’s opposed market-rate new home construction, a stance that’s getting renewed attention due to his presidential campaign, and his recent tweet about a project in Boston. This shows the difference between Sanders and his far more pro-housing Democratic primary competitors, causing some commentators to call him an aspiring Nimby-in-chief.

Last week, Sanders tweeted about Suffolk Downs, a megaproject on Boston’s east side that has endured years of community review. Now close to approval, Sanders tweeted that he opposed it from fear that it would displace people in the heavily-Hispanic area.

But this was a poor characterization. The project, which is being developed by HYM Investment Group, won’t displace anyone, as it’s being built on a now-defunct horse-racing track. HYM proposes, in what would be one of America’s largest redevelopment projects, to build 10,000 housing units (including 1,400 affordable ones on- and off-site); 450,000 sq.ft. of retail; 6 million sq.ft. of office space and hotels; and 50,000 sq.ft. of public indoor civic space. The project would create 24,000 new permanent jobs, add $80 million to property tax rolls, and go near existing transit.

It might seem crazy for Bernie to oppose a project that brings so many positives, and so few negatives, to a city with a severe housing shortage. But he’s engaged in such NIMBYism for decades, even starting his political career that way.

In a lengthy piece titled “Is Bernie Sanders A NIMBY?”, Mother Jones notes that he was elected mayor of Burlington, VT in 1981 on a platform to oppose market-rate development—namely a waterfront revitalization including a hotel and condos. After being elected, he helped approve a new plan to put most of that land under public ownership. While in office he also tried to pass rent control measures—an effectively anti-development effort—and created a land trust program that placed 7% of the city’s housing stock under non-profit control.

Since becoming a senator, Sanders has backed anti-housing candidates, recently through Our Revolution, the PAC spun from his 2016 presidential bid. The PAC supports progressive-left candidates, which recently has meant ones who run against center-left, pro-growth YIMBY candidates. This occurred in Cambridge, Berkeley, and most famously San Francisco, where Bernie’s endorsement of Jane Kim for state senate helped her nearly beat Scott Wiener, who has since tried to pass multiple state housing bills.

Sanders’ presidential campaign this time around has echoed his previous ideas. His “Housing For All” plan could technically be called pro-housing, since he wants to spend a whopping $2.5 trillion to build and repair affordable housing, including public housing. But he’s shown continued hostility to housing that’s built on the open market, free of government control and money. “Housing For All” calls for universal rent control, and the wide use of anti-eviction measures, which would discourage rental apartment construction and potentially decimate the rental market altogether. He has spoken out against market-rate projects in Boston and beyond. Mother Jones noted in its piece how this distinguishes him from rival candidates:

At the NAACP presidential candidate forum in July, Sanders’ chief rival for the left-leaning bloc of Democratic voters, Sen. Elizabeth Warren (D-Mass.), told the crowd, “I have a plan to build about 3.2 million new housing units in this country.” Sanders, by contrast, thundered, “We’re gonna tell the developers: You just cannot come in and build expensive condominiums!”

Bernie Sanders through the years, then, has been pro-housing in theory; but his approach is so ideological as to be anti-housing in practice. He thinks housing should be massively funded by the government, and operated under a public, social, or non-profit model. If it’s not delivered like this, he’s seemingly against it, and willing to signal boost politicians and activists who block it.

Even those who, unwisely, like the idea behind Sanders’s approach should see that it’s unrealistic. The prospect of Sanders being elected president and passing a huge home spending bill is unlikely, and if it happened, would take years to unfold. In the meantime, cities like Boston and San Francisco need housing now, however it’s provided. Sanders’s dogmatism on the issue is not only ironic, given that he owns three private homes, but also counterproductive—the classic case of favoring ideology over the needs of real people. In other words, he’s a Nimby.