The president lashed out at the Democratic Maryland congressman on Saturday, calling him a "brutal bully" and describing Baltimore, part of which is in Cummings' district as a "disgusting, rat and rodent infested mess" in which "no human being would want to live."
House Speaker Nancy Pelosi defended Cummings on Twitter and rejected Trump's "racist attacks against him."
Hostin, a former Baltimore resident, called the comments a "distraction" on Monday.
"I lived in Baltimore. I met my husband in Baltimore. My son was born in Baltimore. I met some of the finest people on the face of the earth in Baltimore," Hostin said.
Hostin went on to point out that Johns Hopkins University, which is in Baltimore, is "one of the finest medical institutions in the world." Johns Hopkins Hospital is also where Carson became an acclaimed and once-celebrated surgeon in the city.
"When you are silent in the face of racism, you are complicit in that racism," Hostin said of the lawmakers and other officials who didn't rise up to defend Cummings.
"As a member of [Trump's] senior cabinet, where is Ben? Why is he not calling it? He's in charge of housing for the Trump administration. Where are you? Why are you not defending Baltimore?" Hostin continued.
Carson faced backlash in May after an exchange with House Democrat Katie Porter during a congressional hearing where he mistook the foreclosure term "REO" for "Oreo" cookies. Hostin called his error "frustrating," in May and said that he's "not placed well" in his current government position, where he appears "unqualified."
"As someone who did grow up in the projects Ben, you are not in the right place," Hostin said of Carson in May. "These are people that need his help. These are people that need him, and he's turning his backs on them."
Every episode of ABC's award-winning talk show "The View" is now available as a podcast! Listen and subscribe for free on Apple Podcasts, Google Podcasts, TuneIn, Spotify, Stitcher or the ABC News app.