Their gripes -- although not necessarily their conclusions -- are, in large, legitimate and could rip the EU apart if they're not addressed.
The countries of the "new East bloc" don't just butt heads with the EU on specific issues such as energy and immigration; they profess a rival big-frame vision for the future: a loosely aligned "Europe of nations."
To begin with, even Central Europe's loudest demagogues, aren't "anti-EU" as much as they are "anti-Brussels," which implies specific disagreements with current EU policies, not the EU.
And this is understandable, and legitimate: The EU has many deep-seated flaws, which even its advocates acknowledge -- although they play down their reservations for fear of further tarnishing the EU's image.
"In Central Europe, the EU hasn't put nearly enough emphasis on internal imbalances within countries," explains Hungarian economist Laszlo Andor, who was Hungary's EU commissioner from 2010 to 2014. "The East-West divide in economic opportunities and social equality in countries like Hungary, Poland and Slovakia is reflected in a divided political map."
Indeed, borderless free trade -- one of the EU's key selling points -- has hurt those beyond the hubs of prosperity, especially in agriculture, who find it difficult or impossible to compete with EU trade-zone imports.
The national populists take aim at the neoliberal economics that they claim are embedded in the EU's DNA. What they offer however -- clientelism and protectionism -- is no real option for economic success. Central Europe's mainstream political parties, which are considered the champions of the market economies that they put in place in the 1990s and 2000s, have paid for the fallout at the ballot box. Progressive left-wing parties are striking absent from the political landscape.
As for EU democracy, the Central Europeans rightly feel excluded from decision-making processes that are dominated by the bigger, wealthier Western countries. The EU's democracy deficits are gaping in the first place -- for all of its 510 million citizens.
But for the smaller, poorer countries, like most of the Central Europeans, they loom even larger. They have scant means to affect policies when Germany and France team up with each other. The EU's processes are opaque, and the biggest decisions are made behind closed doors.
The Western countries often act as if the Central Europeans are fortunate just to sit at the table with the grown-ups. They shouldn't be complaining about the fare. This arrogance in Brussels has finally gotten under their skin after years of silently enduring it -- and populists exploit this resentment to the fullest.
Of course, the Central Europeans are increasingly unhappy -- and vocal -- about the liberal cultural manifesto that came with their EU entry -- the fine print, as they saw it when they signed up.
Yet tolerance of homosexuality, for example, or other civil rights issues didn't manifest themselves as from-below social movements in Central Europe as they did in Western Europe in the 1970s, and gradually, over decades, become the norm.
We have to remember that only when Western Europe's postwar economies stabilized did "post-material" values, such as gender equality, self-expression and environmentalism, become serious issues -- and then were institutionalized piecemeal over the course of years with conservatives fighting them every step of the way.
This is no excuse for discrimination, for example of the Roma people or gay people, or the rejection of immigration, which is currently at the crux of tensions. These are fundamental rights at the heart of the EU project.
But perhaps the Central Europeans should be measured in terms of their progress in the right direction, rather than the current state of affairs. The tragedy is that there won't be any progress with blinkered nationalists in power. But this vicious circle will become all the harder to break, the longer the status quo prevails.
Tragically, the animosity between the Central Europeans and the EU looks only to worsen.
Macron and Merkel, as just about everyone in the EU, realize that the EU needs fixing. But the plan to create faster and slower tracks for countries on different issues will only further empower the larger Western countries at the expense of the smaller ones.
Berlin and Paris believe that they will chart the course, and the rest will follow. But if this is the terms of reform, one day the Westerners might wake up to find that the followers have opted for their own path.