I hope they plan to do that if any president decides to refuse to leave office.
The Constitution is very clear on the matter: a president's term ends on Jan. 20 following the most recent presidential election. Period. If the incumbent president was not elected to be the president for the four-year period that starts on that Jan. 20, then the entire military structure should refuse to cooperate with that incumbent.
Stating that this is a new-found resolve by senior generals solely on account of President Trump is either a slur on the military brass generally, or a slur on President Trump, because he never made any comments about overstaying the end of his first term on Jan. 20, 2021, except in the event that he was re-elected to sit for the next four-year term.