not ONE dualist understands Advaita. Advaita is not a set of words about the nature of humans,Gods, Moksha etc. - it is a directly experienced wordless state.
Ramakrishna Paramahamsa expressed it best
SANKARACHARYA AND HIS FOOLISH DISCIPLE
THE great Sankaracharya had a foolish disciple who used to imitate his Master in all matters. Sankara uttered 'Sivoham' (I am Siva); the disciple also repeated 'Sivoham'. To correct his disciple's folly, Sankara one day, while passing by a smithy, took a potful of molten iron and swallowed it; and he asked that disciple also to do the same. Of course, the disciple could not imitate this act of his Master, and thence forward he left saying 'Sivoham'. (52)
There are numerous word-level counters to Advaita from Theistic schools that mean nothing. Mandanaamisra is said to have refuted Buddhism by joining a Buddhist monastery and learning all their teachings before refuting them.- I haven't heard of ONE dualist who actually experienced Advaitic truth and claimed it was false AFTER that.
Ramana Maharishi explains the stages of achieving the highest Advaitic truth: