By saying that institutions accomplish the creation of gender. Kimmel is referring to the way we’ve organized society and in this case work or school environments to favour old time gender roles. If there is a stay at home parent present in the home it is often more beneficial for it to the the woman just because of how society is arranged.

What Kimmel means by the plural “masculinities” are both the cultural differences associated with the ideal man, and also the differences in different time periods. For example a white middle class man in the 50’s would have a different idea of what it means to be “a man” than a young boy in todays day and age. But both examples are still affected by the social pressure and unfair constrictions of what we’ve excepted as being a “man”. By saying “Masculinities” we are understanding and including certain discrepancies within the meaning.