Poe'e law states that there's no such thing as satire, and that every post that could be considered a joke is actually a display of incredible stupidity
Not really. Poe's Law just states that extremist positions are often impossible to distinguish from satire. It doesn't say that there's no such thing as satire.
That's why I append my sarcastic posts with /s. It's a habit I picked up on Reddit where you could easily see someone posting that same comment, but being 100% serious. The /s kind of ruins the joke, but I'd rather the joke be ruined than have people think I was serious when I said those kinds of things.