“America will not see herself in full” when the seventh Democratic debate takes place in Des Moines, Iowa, on Tuesday night, Deval Patrick said, citing an absence of candidates of colour.

The former governor of Massachusetts is the only African American candidate left in the primary, after the New Jersey senator Cory Booker withdrew on Monday.

Patrick entered late and remains well off the pace in both poll results and donations, criteria used by the Democratic National Committee to determine debate qualification.

On Monday, he responded to Booker’s departure by tweeting: “Whether it’s behind closed doors or screaming it from the rooftops – every candidate in this race needs to say it out loud: women and people of colour can win. To say otherwise expresses a lack of faith in the American people who deserve more from their leaders.”

In a statement on Tuesday, Patrick slammed the debates as “an episode of reality TV” divorced from the concerns of everyday Americans, particularly the impact of racism.

“The debates have become an end in themselves,” he said, “an episode of reality TV with candidates paying more attention to polling numbers and donations than issues and people.”

The debate in Iowa on Tuesday night will be contested by former vice-president Joe Biden; Vermont senator Bernie Sanders; Massachusetts senator Elizabeth Warren; Minnesota senator Amy Klobuchar; former mayor of South Bend, Indiana, Pete Buttigieg; and Tom Steyer, a billionaire hedge fund founder and climate activist.

Patrick said those who would debate were all “remarkable public servants. Yet tonight, America will not see herself in full.

“The racial and ethnic diversity of the Democratic field and our willingness to speak directly to issues of racism, has made me proud to be a Democrat and an American. But the debates have stopped either showcasing the field or representing the nation.”

Booker followed the California senator Kamala Harris and former housing secretary Julián Castro in dropping out of the race. Booker and Castro failed to qualify to appear in later contests. Patrick said “it concerns me that not being on the debate stage has contributed to that”.

Criticism of the Democratic field for being too white has been widespread, particularly since the downfall of Harris, who showed strongly after challenging Biden on racial issues in an early debate but could not build on her place in the polls.

“It’s galling for people that are on the stage to not acknowledge and speak to black women’s issues,” Aimee Allison, founder and president of She the People, told the Guardian after Harris withdrew.

“You don’t have to be a black woman like Kamala Harris to carry issues important to us. But you do need to acknowledge you’re not going to get anywhere without our vote.”

Patrick echoed that concern, saying Democrats could not beat Donald Trump in November “without voters of colour, nor should we”.

Among black Democratic voters, Biden, boosted by his eight years as vice-president to Barack Obama, holds a strong national lead over Sanders.

Patrick cited key issues to voters of colour including environmental justice, gun safety, health disparities and mass incarceration. None of the candidates onstage in Iowa, he added, “knows what it’s like to fear for their safety when pulled over for a routine traffic stop.

“No one on that stage has ever been questioned about their citizenship or if they’re a ‘real’ American or been followed by store security when shopping. No one has ever asked themselves whether a rejection for an apartment or a loan was because of their race …

“Surely the leadership of the Democratic party must now see that the criteria chosen have not served to demonstrate to Democratic voters or to the nation the breadth and depth of diverse talent in the field, and must reconsider the criteria for participating in, as well as the format for, future debates.”