There's a huge difference between being commanded to "Do the Dishes, Put Out, Don’t Talk So Much" by other people, versus doing these things on your own initiative as part of your relationship.
If smallblacksun wanted to refer only to stereotypes about gender roles he/she should have said 'those stereotypes exist for a reason.' Instead he/she said 'stereotypes exist for a reason,' which is a much broader statement.
>Because it's [stereotyping is] easier than critical thinking?
In a way, yes.
In fact stereotyping is like writing a script rather than repeating the same process over and over. You may need to amend the script for a given situation of course, but it serves as a useful first approximation of a solution.
It is critical thinking that leads one to effective use of stereotypes: it's not always raining when it's cloudy outside but it's a useful indicator.