Bruce Springsteen's pissed President Donald Trump wants to compensate people who stormed the Capitol on January 6, 2021 ... calling it an "American outrage."

The rocker roasted DJT at a concert in Washington, D.C., Wednesday night ... launching into a rant against the prez which reportedly lasted about 6 minutes -- and he made it clear he's not supporting taxpayer dollars going to people who assaulted police officers.

Springsteen says he's outraged by Trump's proposal for a $1.776 billion fund to pay out people who attacked American democracy back on January 6, 2021.

As you know ... Springsteen's no fan of the current administration -- most recently blasting Trump and his allies during a tribute to Stephen Colbert on one of his last 'Late Night' shows.

Springsteen isn't the only person pissed about the proposed fund ... two police officers at the Capitol on J6 are suing the Trump administration for proposing it -- calling the fund the "most brazen act of presidential corruption this century."

The Boss's "Land of Hope & Dreams" tour ends Saturday in Philadelphia ... but don't expect Springsteen to fade away from the political sphere. He's announced a festival near D.C. scheduled for October 3 -- one month before the midterms.