That is true...nor did the Congress go public about their issues nor did they send a letter to the Kremlin.
Actually there’s a long history of Congress critters meeting with or communicating with foreign leaders including some meetings many of us still remember with considerable pain as kerry helping the communist northViet namese ( while we had a half million of our troops fighting there!) —to the extent they have a full museum display dedicated to him, and his meeting with commie Daniel Ortega and pelosi meeting in person to discuss foreign relations and military questions with Assad in Syria and we could go on and on. The senators’ letter merely recited the U.S. Constitution something that is even more important today now that kerry has revealed obama never planned to let the senate do its constitutional advise and consent on his proposed (non-) treaty anyway.