Firstly, I didn't say his ideas are dumb. I said you have a right to hold dumb ideas.
Secondly, some ideas are dumb, some ideas are quackery. It's a good thing to recognise that fact. If you don't like the terminology, well, I'm just saying it like it is.
Using the terms "dumb" or "quackery" really lowers your persuasion.
Using your own vocabulary: I guess your "shit" didn't stick to the wall. :)