In his book The Armchair Economist, Steven Landsburg points out that “Most of economics can be summarized in four words: ‘People respond to incentives.’ The rest is commentary.” If you want to know why the US Women’s National Team kept scoring even when their game against Thailand was out of reach, look no further than their incentives.

In just a few hours, the US Women’s National Team kicks off its second game of the 2019 World Cup Tournament. Presumably, Chile will present a tougher challenge than their opponents from June 11’s first game [update, afternoon of 6/16/19: they did; the US still won 3-0, but stellar goalkeeping by Christiane Endler kept it from being far worse]. Led by five goals from Alex Morgan, US set a World Cup record in a 13-0 shellacking of an almost-absurdly overmatched Thailand team. Here’s a recap from Fox Sports.

In the game’s aftermath, the team came under fire for running up the score and for celebrating so much after each goal when the game was clearly out of reach.

It’s a no-win situation for the team. If they celebrate, they’re “rubbing it in their faces,” as former USWNT forward Sydney Leroux told The Atlantic. As she continued, “You don’t, and you’re entitled or cocky.” There’s the simple fact that scoring a goal in the World Cup fulfills a lifelong dream for the players. Who wouldn’t be overjoyed?

More deeply, though, who are they to argue with their incentives?

As commentators and players have pointed out, scoring a lot means a greater chance of advancing. According to FIFA’s regulations for this year’s World Cup, if two teams finish with the same number of points after group play (three points for a win, one point for a draw) the first two tiebreakers that determine who advances are goal differential (goals scored minus goals scored against) and, if that’s the same, total goals scored.

People might argue, perhaps correctly, that the USWNT didn’t need to score a record-breaking thirteen goals against an obviously overmatched opponent, but suppose the score had been much closer and people had asked “why’d the USWNT let off the gas?” I suspect they’d have been dismissed as arrogant—“entitled or cocky,” perhaps?—had they said “we doubt we’ll need to worry about the tiebreakers for advancement into the knockout stage.”

Was the USWNT being a bunch of bad sports in decimating Thailand 13-0 and celebrating along the way? Maybe, but I doubt it. And if you disapprove, consider their incentives. Indeed, this is the first place anyone should look when trying to understand or explain human action—and the ladies’ response to their incentives are, I think, a much better explanation than bad sportsmanship. Are incentives always and everywhere decisive? No, but they definitely guide and change people’s behavior.