It is true to who they are and a character-driven quarrel that will hopefully last more than two episodes.
Just like there was no reason for Arya to trust or be close to Sansa in Season 7 immediately, there is no cause for Sansa to believe in or like Daenerys.
Will Daenerys change Sansa’s mind about her?
It is a relief to see Sansa speaking the truth about the Mother of Dragons.