I always felt that JA approved of the way that Mr Bennet mocked the foolishness of Mr Collins. In her own life, she thought and wrote these comments but would not have spoken them in company. I think she enjoyed voicing them through her literary creation who, as a patriarch, was allowed to express opinions she could not.

I think she identifies with Elizabeth here: she agrees with his comments and finds them funny but, as an unmarried woman, is not allowed to express her own opinions and must obey the rules of etiquette. JA probably sat through many an evening such as this, biting her tongue.