One solution to this problem, which seems to crop up repeatedly, would be to stop asking "obviously over-the-top questions" and instead just say what you mean.
Sometimes it is better for people to figure out for themselves why something (like the Penny Plan) isn't likely to work than it is to tell them. If you just tell them, they might take--what did you call it--an ad hominen point of view to re: the person that is saying the plan will not work.
On the other hand, if you ask them to explain how it will work--how a certain flawed feature can possibly work--then can see for themselves that it doesn't add up.
But, hey, I am open minded and if "GOP-sympathizers" are getting behind a plan that balances the budget using increases in revenue to get us 80% of the way their and cuts to spending to get us 20% there, I'd love to hear more. For me, that is too much $$ coming from more tax revenue and not enough coming from spending cuts, but I am trying to be "better informed, more intellectually consistent, more open-minded, more empathetic and more receptive to criticism."