You can at least understand why some elected officials prioritize public over private schools. They are, after all, the schools for which those officials are responsible, the ones their constituents fund and that most of the children of those constituents attend.

What’s much harder to defend is officials favoring certain types of public schools over others, as Boston Mayor Michelle Wu has done with “BPS Sundays,” a new pilot program that provides Boston Public Schools students and up to three guests free admission to six major Boston museums, including the Franklin Park Zoo and New England Aquarium, on the first two Sundays of each month through August.

It’s a great idea, but other Boston public school students — such as those who attend charter public schools and the METCO program — need not apply, and it’s a stretch to believe politics doesn’t have something to do with that.

METCO is a voluntary racial integration program that sends over 3,000 mostly low-income Boston students to suburban school districts. Last year, a comprehensive Tufts University study compared the performance of those students to those who applied to METCO but weren’t selected in the admissions lottery.

METCO students did better across the board on MCAS, their SAT scores were 30% higher, students were a third less likely to drop out, 17% more likely to attend college, and 6% more likely to graduate in four years. By age 35, they earn about 60% more than those who applied but were not selected.

METCO’s success at narrowing race- and income-based achievement gaps is further magnified by the study’s finding that student gains are even larger among those whose parents didn’t attend college.

The 13,000 Boston students who attend the city’s 20 charter schools outperform BPS by an even larger margin than METCO students do. Many of them are also low income, unable to afford — as Herald columnist Joe Battenfeld wrote — the more than $100 tab for taking a family of four to the Aquarium.

BPS Sundays isn’t the only way in which public officials discriminate against those who attend non-favored public schools. Despite its success educating disadvantaged students, the Commonwealth hasn’t expanded METCO in decades.

Municipalities pay for traditional public-school buildings. In Boston, that means the more than $31,000 per pupil annual spending — second only to New York among the nation’s 100 largest cities — only covers operating costs.  Massachusetts charter schools must stretch their funding allotment to also pay much of the facilities bill.

It’s hard not to notice that it’s the schools and programs that are most successful at educating low-income kids that routinely draw the short straws in the through-the-looking-glass world of Massachusetts education politics. That may not be an accident; they are the schools and programs that are most threatening to a status quo that wields vast political power in Boston and across the Commonwealth.

Academically successful education options aren’t tolerated because they lay bare a fundamental myth: All that’s needed to improve districts like BPS is a little more money.

Charles Chieppo is a senior fellow and Jamie Gass directs the Center for School Reform at Pioneer Institute, a Boston-based think tank.