One of the core principles of DBT is “acceptance”. I think the nomenclature can be quite misleading.
But what the term is supposed to mean is “you should not deny reality”
Litany of Tarski (paraphrased bc I have no internet connection atm)
“What’s true is already so. Admitting that won’t make it any worse. If X is true, then I want to believe X. If X is true then I can “stand” fact X; I already am. If X is false, then I want to believe not X. ”