Bill Barr got his law degree taking evening classes while working as an intelligence analyst for the CIA and graduated with the highest honors the school can give. He has then climbed up the ladder in the DoJ to become the AG in 1991. He then goes on to have a fantastic legal career in private life that ends with him on the board of directors for Time Warner. In 2019, he finds himself back in the AG chair. As far as legal resumes go, he is in the top 1% of 1%. That should tell you that when someone with that kind of resume says something that blatantly runs against Constitutional law or the democratic processes on which this country functions, they aren't misquoting or misunderstanding a Constitutional concept. They're telling you how THEY think it should be.
Cruz, for example, graduated from Harvard Law magna cum laude, was the editor of their Law Review, and was regarded as a brilliant student. He then went on to be the first Hispanic to ever clerk for the Chief Justice of the Supreme Court. He was part of the Bush legal team in Bush v. Gore and was Texas Solicitor General at the age of 33. An off the charts legal resume. Top 1% of 1%. I'm certain that if he were to sit down with 99% of the attorneys in the nation to talk Constitutional law and the cases surrounding it, he would embarrass them all outside of people who are Constitutional scholars for a living. Yet, we see him get pantsed on a regular basis when he's holding his ground on his own positions. That's not because he's stupid, in a legal sense. He just doesn't believe that a lot of the law that stands today should be the law and wishes to replace it with his own vision.
People like Barr and Cruz in the government aren't misspeaking when it comes to the law. They're telling you how they think it should be and are actively working to change it. For someone like Cruz, that's part of his job as an elected official. But when it comes to someone like Bill Barr, it is insanely problematic. His job is to enforce the law, as it is today, and advise the executive branch of the law when necessary. The way mail-in voting currently works is the law of the land. He knows it is. But here he is waxing poetic about the loss of the secret vote, conjuring up hypothetical fraud, and then projecting that fraud onto those who he sees as political opponents. Sure, he is entitled to have an opinion, but if Eric Holder went into an interview and questioned the validity of the 2012 election 2 months before election day, it would be an absolute political firestorm and rightfully so. Barr says something like this, Trump latches onto it, and it feeds an already dangerous, out of control rhetoric regarding the 2020 election.