Earlier this week, Joaquin Castro shared a list of names of San Antonians who gave Donald Trump a maximum donation. Since then, the Congressman has faced backlash. Conservatives, in particular, have accused Joaquin of doxxing Trump supporters. In an interview with MSNBC’s Morning Joe co-host Willie Geist, Castro elaborated his decision to share the names and didn’t give in to pressure to apologize.

Despite Geist telling Castro that donors were “undoubtedly already being harassed online or perhaps face-to-face in some cases” because of his tweet, the Congressman said that his intention was to start a dialogue.

“What I hope is that this has started a conversation about what exactly Donald Trump is doing with these people’s money,” he said. “And I hope donors in San Antonio and donors throughout the country, unless you support the white nationalism and the racism that Donald Trump is paying for and fueling, then I hope that you, as a person of good conscience, will think twice about contributing to his campaign.”

Geist accused him of putting people’s addresses out in the public (he didn’t) and wondered what Castro wanted from these donors. “Do you want them to repent for their support of President Trump or what do you want from them?” Geist asked.

But Castro stood his ground and explained that he merely put out details that are already public. “What I want is for people to think twice about supporting a guy who is fueling hate in this country,” he said.