I actually don’t know the details of the specific crimes. Eg if you’re a soldier and you post on Facebook that you’re about to go on a raid to depose a head of state, that’s presumably a secrecy violation you would be punished severely for. The insider trading can be like this too in that you’re improperly using the information you are privy to due to your being an insider. If you’re a congressperson and you tweet that the government is about to do such a raid, I don’t know what the legality of that is – perhaps you have some kind of privilege to reveal these things and any censure must happen politically (eg impeachment, losing elections, etc) rather than legally. I don’t know what the rules for insider trading would then be – legislators are not insiders in the way that soldiers are.
Ignoring the moral argument, it isn’t all that clear to me that this would actually be a crime for a legislator under US securities law. It may be that new laws would be required to be able to punish legislators for this kind of behaviour.
Congress sometimes includes an exemption for themselves from some crimes. Others are excused by the Constitution:
> The Senators and Representatives shall receive a Compensation for their Services, to be ascertained by Law, and paid out of the Treasury of the United States. They shall in all Cases, except Treason, Felony and Breach of the Peace, be privileged from Arrest during their Attendance at the Session of their respective Houses, and in going to and returning from the same; and for any Speech or Debate in either House, they shall not be questioned in any other Place.
Explanation:
https://constitution.congress.gov/browse/essay/artI-S6-C1-2/...
As for insider trading:
> The law prohibits the use of non-public information for private profit, including insider trading, by members of Congress and other government employees.
https://en.wikipedia.org/wiki/STOCK_Act
He was charged with "unlawful use of confidential government information for personal gain, theft of non-public government information, commodities fraud, wire fraud, and making an unlawful monetary transaction.". Supposedly, unlawful use of government confidential information could also be applied to legislative and other people in the government