They're partly right. The US has some aggressively stupid educational policy such as teaching reading via 3 cueing (which I won't go into here), but they've also fallen for a bit of accounting trick.
Most obviously, schools being funded via property tax in most states means rich districts tend to receive more money than schools in poorer districts. Less obvious is that because the US doesn't offer many services generally those that are offered are often routed through the schools and attributed to the education budget e.g. many kinds of therapists and aides are part of school budgets in the US but are part budget under various health department budgets in other countries and thus those countries' total spend on students is undercounted.
Similarly, countries that invest in making sure there are enough social services to ensure a good life for even the bottom 20% of society need to spend a lot less fixing the problems that arise from growing up with a bad home life and get more bang for their buck.