Their beliefs have a negative impact on public policies. While it may be in vain, I don't think it's wasting one's breath.
Besides we're not on a submarine there is plenty of breath to go around.
I have a wife and a mother in law who have those "beliefs". At first I was all about wasting the breath, but now? I'd rather let my vocal chords have a break. In fact, I almost always get up and find a reason to leave the room. My sanity is much more in tact since I started doing these things.
If God got into a fight with Chuck Norris, who do you think would divide by zero first? This is a serious question.