First, you can't comment by gender. Now the society is completely equal between men and women, so there will still be such a gender-based tone of voice, which will make me feel ridiculous. Boys and girls look at things in a somewhat different way. Zhang Chaoyang's remarks may be because men are more rational than women when thinking about problems in school, so he thinks that boys can learn mathematics and physics well. But personally, I don't agree with his view that girls can't learn math and physics well, because I have known many female schoolmasters since I was a child, and their scores in math and physics are very good, and their total scores are even better than those of other boys in the class. According to this phenomenon, Zhang Chaoyang's remarks cannot be explained, so I think he is sexist.
Second, we cannot generalize. It is true that in high school, many girls will choose liberal arts classes and many boys will choose science classes, but this does not mean that girls can't learn math and physics well, just that girls and boys have different hobbies. Girls are much more careful than boys in their studies. As long as these girls are willing to spend time studying mathematics and physics, their scores will not be worse than those of boys, so Zhang Chaoyang's statement is too extreme to convince everyone.
According to Zhang Chaoyang, it seems that most girls are not qualified to study science, because mathematics, physics and chemistry directly determine the results of science. Such sexism makes us women feel very uncomfortable. We don't agree with this view either, because many female schoolmasters emerge every year, and their achievements in mathematics and physics are still excellent.