Don't thank me for my service

I typically ask business if they give discounts to disabled veterans and regardless their policy, the cashier will often say, "Thank you for your service."

First - I typically want to tell them you should spit in my face for supporting a government that routinely takes action both domestically and in foreign policy to undermine democracy and freedoms.

Second - I want to ask them do they know their city, county, state, or national representatives, any of the pending legislations being currently debated, or have they written their reps about ANY topic they find important recently. Voting in a popularity contest every two years, then sitting on your ass so someone else can think for you isn't honoring those that have served, suffered, or died.

My question - how can I convey this without sounding like a bitter, judgmental asshole? My goal is to get people to stop being so apathetic and lazy, and start taking a more active role in directing their government and informing themselves of what's going on in the world.