"They could do so much if they decided to use their stupendous level of popularity to fight racism."

Soccer superstar Megan Rapinoe clearly ain't happy with the efforts Lionel Messi and Cristiano Ronaldo have made to try to stamp out racism ... and now, she's urging them to do far more.

"I’m not talking about wearing a Black Lives Matter T-shirt," Rapinoe told L'Equipe Mag this month. "I’m talking about going deeper."

Racism is still a huge problem in international soccer -- particularly in 2019.