Okay, let me explain like you are five years old.
Critique of ideology means looking at the ideas that people have and trying to figure out if they are really true or if they are just something people say because they believe it.
Ideology is like a set of ideas or beliefs that we have. Sometimes these ideas are correct, and sometimes they are not.
For example, some people believe that girls can not be good at math. That is an ideology.
The critique of ideology is when someone looks at that idea and tries to figure out if it is true or not.
In this example, if someone did a critique of ideology, they might find out that girls can be just as good at math as boys.
Basically, it is just questioning what people believe to try and figure out if those beliefs are actually true or if they are just something we believe because we have always believed it.