I think CBC’s recommendation is code for “even WE want her out of Congress”
No, I think what happened is that SJL had this "revelation" that she could be DHS Secretary. Kind of like me having the revelation that I could be the CEO of Apple.
So, she went to her fellow CBC members, and asked: "wouldn't that be cool?". And they said: "Yeah, if a white woman can be DHS Secretary, why not a black woman? We need more black women in the Cabinet!"
It's racial identity politics, nothing more.