Likely not insider trading, but it would obviously be a fact-sensitive question that depends on what exactly was said behind closed doors.
For example, if you work for an organization that assembled a CV task force and regularly updated its employees on the evolving threat, surely you wouldn't be guilty of insider trading if you changed some of your positions in the market based on how that information affected your outlook on the future.
The question should be whether they were trading based on confidential or privileged information.
BTW, you're kidding yourselves if you don't think Congresspeople do this crap all the time. You can't unlearn information, and as long as a regular investor could learn the same information with some diligence, we've decided it's fair game.
I suppose we could forbid Congresspeople from trading in equities, but they could still pass along their hot tits to others.
