Yeah, like, I could say that I'm concerned about a leader in the Railroad being a former member of a xenophobic organization that has a history of advocating genocide, and I could start demanding that you reveal every detail of everything you did while a member of that organization.

But I won't, 'cause, like I said, I'm not a jerk and I know you're loyal to the Railroad now.

[And also he still has access to those Enclave personnel files that the Brotherhood of Steel acquired. He can find out for himself what Carrington did for the Enclave. But Carrington doesn't need to know that.]