They are, however, falling afoul of the generalized version of Poe's Law [0]. If you want to satirize positions like this on the internet, you really need to leave some indication that that's what you're doing. If you just remain committed to the bit, you will look exactly like the very real assholes who believe these things unironically.
Hard disagree. Satire is never labeled as such. By identifying sarcasm or sardonicism, you would basically be saying that the comment is not inherently absurd enough to be immediately recognizable as laughably wrong. The whole point of sarcasm is to highlight absurdity.
There will always be people who misinterpret this kind of writing. That doesn't make it bad writing; some people are just a little dumb. The writing isn't for them.