People in general, they understand Vedāntist means Śaṅkara sampradāya. Because the devotee class, they do not give much importance to Vedānta. Because they read Śrīmad-Bhāgavatam, and Śrīmad-Bhāgavatam is accepted by the Vaiṣṇava-sampradāya, especially by the sect of Caitanya Mahāprabhu, as the real explanation of Vedānta; therefore they do not give any other explanation of Vedānta than Śrīmad-Bhāgavatam.
And because the Vaiṣṇava-sampradāya does not give very much importance to Vedānta-sūtra—because the explanation is there, they are reading actually Vedānta-sūtra—people misunderstand that the Vedāntist, followers of Vedānta, is the Śaṅkara-sampradāya, not this Vaiṣṇava-sampradāya. That is their misunderstanding.