Serious question, Ned...do you believe that Sen. Markey never discussed his plans to visit Taiwan
with President Biden, and/or his Secretary of State?...that this trip is a total surprise to the administration?...of course you don't...therefore, you have to agree that it's a purposeful act with the approval of the administration...it's clearly the way they choose to deal with Xi...no problem with you disagreeing, though.
IMO, this visit is an extension of the "message" Pelosi's visit sent...i.e. the USA will make its own decisions on where and when to go in the world...which, btw, was approved by a bi-partisan group of Senators (see link).