Democrats call out lack of diversity in 2020 race after Harris' exit

Why it matters: The six candidates who've qualified for the upcoming debate are all white: former Vice President Joe Biden, South Bend Mayor Pete Buttigieg, Sens. Bernie Sanders, (I-Vt.), Elizabeth Warren (D-Mass.), Amy Klobuchar (D-Minn.) and billionaire Tom Steyer.

• Booker noted on MSNBC that the Democratic race is "spiraling towards" a December debate that "could have six people with no diversity whatsoever."

The big picture: Harris had qualified for the next debate, but she bowed out after struggling in recent polls. The other candidates of color have yet to meet Democratic National Committee debate requirements. Candidates have until Dec. 12 to qualify.

• Fox News notes businessman Andrew Yang and Rep. Tulsi Gabbard (D-Hawaii) met the donor threshold qualification "but have yet to meet the polling requirement."
• Neither Booker nor Castro have qualified met the requirements so far.

What they're saying: Several liberal activists and progressive groups have spoken out on the lack of diversity in the Democrats' race now.

• Democratic strategist Michael Starr Hopkins told Fox News the DNC "thought it would help progressives" with its new requirements, "but it ended up hurting campaigns like Harris, Booker, and Castro. "Instead of focusing on building infrastructure, they had to spend insane amounts on donor lists to get on the debate stage," he said.

• Castro told BuzzFeed the media had held Harris to a double standard because candidates of color are treated differently. He also addressed the DNC debate's diversity issue in a video posted to Twitter.

Go deeper:

• Kamala Harris drops out of 2020 presidential race
• 2020 presidential election: Track the candidates
• "Axios on HBO" interview with Kamala Harris