It is something to criticize, especially so if it's a value the Republican party admits to not caring about. It also makes the current tension all the more interesting, it's unusual for there to not be unity
You said representatives aren't supposed to represent their constituents - who are they supposed to represent?
Reality is that they frequently tend only represent their constituents enough to remain in power while focusing on representing their donors, but they should be representing their constituents - that's literally how the model is designed and defined.