Politicians may love to praise charter schools, but John Oliver opted to take look into their operations on Last Week Tonight Sunday, and came up with some rather disturbing findings.

“Charter schools unite both sides of the aisle more quickly than when a wedding deejay throws on ‘Hey Ya,’” he said. “Charters are basically public schools that are taxpayer-funded but privately run. The first ones emerged 25 years ago as places to experiment with new educational approaches.”

He went on to explain that there are currently more than 6,700 such schools — including ones launched by celebrities including Andre Agassi, Puff Daddy, and Pitbull — educating nearly 3 million students.

“For this piece — and I know this is going to make some people on both sides very angry — we’re going to set aside whether or not charter schools are a good idea in principle, because whether they are or not, in 42 states and D.C., we’re doing them. So, instead, we’re going to look at how they operate in practice,” he said.

Oliver then pointed out that “around the country, there have been charter schools so flawed, they don’t make it through the school year,” before diving into some of the entities that oversee such schools, especially in Florida, Pennsylvania, and Ohio, where some have folded just six weeks into the school year. The cause? A lax approval process, as well as administrators who’ve been arrested for theft and embezzlement of school funds.

Nearly 180,000 students “attend” online charter schools, which have some additionally frightening statistics. In most cases, states require attendance records, so all students are marked as present every day, whether they logged in or not. “You’re basically giving kids a box that contains video games, pornography, and long division and claiming 100 percent of them chose the right one,” Oliver said. “One major study found that compared to students in traditional schools, students in online charters lost an average of about 72 days of learning in reading and 180 days of learning in math during the course of a 180-day school year.”

To summarize, Oliver recalled comments Ohio Governor John Kasich made about charter schools creating positive competition for public schools, comparing them to pizza shops. “The problem with letting the free market decide when it comes to kids is that kids change faster than the market, and by the time it’s obvious the school is failing, futures may have been ruined,” Oliver said. “So if we are going to treat charter schools like ‘pizza shops,’ we should monitor them at least as well as we do pizzerias. It’s like the old saying: Give a kid a s—-y pizza, you f— up their day; treat a kid like a s—-y pizza, you could f— up their entire life.”