Fair is fair, what person facing possible criminal jeopardy for criminal conspiracy, aiding and abetting obstruction of n official proceeding, obstruction of justice, etc. would possibly speak to authorities without first having the authorities turn over every piece of evidence they intend to use against them?
So Kevin McCarthy, top Trump loyalist in the House, and always pugnacious former assistant college wrestling coach, Jim Jordan, both refused to comply with Congressional subpoenas unless the January 6th Committee first tells them exactly what evidence they have against them so they will know how to respond, consistently with each other, to questions during their involuntary testimony.
This standard precaution is particularly necessary if the authorities trying to force you to speak under oath are deadly pedophile enemies who are also totally illegitimate and therefore have no right to send subpoenas to anybody that can’t be casually tossed into the toilet with no consequences except an ostentatious flush. Fucking common sense, yo.