Definitely would NOT call her out. She has reasons for her beliefs, true or not. She is unlikely to say "you were right".
We had similar situation. A gifted teacher insisted my child was barely even gifted because she was so quiet. We asked for a grade skip (child was struggling and needed out of elementary school) and this teacher "would never do that to a child". Our plan was to skip this second time and then pull out to homeschool for a year to undo one of the skips.
We got the grade skip. GT Teacher gave dd a project to do on genital mutilation (trying to prove dd was not mature enough to be twice skipped). And GT teacher said dd would not be allowed in twice accelerated math (4 years for her). We said no problem. We are not trying to have her in the top and we're going to undo the skip anyway. Within a couple months, she sent us an email begging us to let dd go into the accelerated math (as if we had said no). Our focus was not on level of academics. It was on social fit and emotional health. The teacher saw that when dd was in a better academic fit, social fit was better as was emotional health. DD started talking and smiling.
FF to After the year of homeschooling. School system wanted to place dd at age level. (which was the same as repeating a grade she had already passed). The GT teacher went to the district and fought for DD successfully. She had become a believer and was dds best advocate.
I truly believe if we hadn't let this teacher see it with her own eyes, she would have continued to work against dd. That's our story. Of course every story will be different.
