To get more extreme: All over the world, people living in poverty lack proper sanitation and enough food. According to our own William Lambers, hunger affects almost a billion people. Living a privileged life in America, I never have to go hungry. Do I deny myself food in solidarity with hungry victims of drought, war, natural disasters, and corrupt government? No. Do I deny myself a vacation because some people, in my own city, can't afford one? No.
When I start doing those things, I can start asking politicians to decline their health benefits and go fend for themselves on the open market.
But I wouldn't. Refusing health benefits may score some political points with the Republican base, but unless these congressmen are going to suffer real hardship by it, it's just grandstanding, and worse: it's an insult to the millions of working Americans who couldn't afford to make such a "statement" if they wanted to.