Apropos simplistic: I have my problems with Maher (some), Trump (a whole lot), Limbaugh (most everything), etc. One problem I don’t have with them is wishing death on those in positions of power who kill people and actively work to kill other people. John McCain falls squarely in that latter group.
I’m not a death penalty proponent. It would be better to send them to the Hague to spend their remaining years playing Risk in Slobodan Milošević’s old cell. Geopolitics being what they currently are, McCain, Emperor Palpatine (aka Dick Cheney), GWB, and their war criminal drinking buddies won’t be on the docket in the Netherlands any time soon. In the meantime, wishing for their quick and non-violent departure from this mortal coil is (IMHO) not being a dick.