Before downvoting, check the community.
If you fail to use the /s tag or specifically call out that your comment is sarcastic, I'm going to treat it as being earnest. I might ask if you're being sarcastic, but I will downvote as though you are being earnest.
The /s tag not only clarifies, but it also confirms that you're being sarcastic. A thing you cannot ordinarily convey via written text unless you specifically call it out. You can hint at it, readers can infer it, but you cannot convey it. To convey it, sans directly stating it, you would need to include a recording of you speaking the comment, which defeats the whole point of text chats.
"It definitely reads as sarcasm, you're just missing it" So what? I'm neurodivergent. I barely get this shit in its normal, spoken context. Why should I be expected to understand the implied sarcasm in your text comment?
"Telling someone you're being sarcastic ruins it" Unless your definition of sarcasm is just lying to someone's face, you do indicate sarcasm when speaking. Via the exaggerated, deadpan tone you use. Something you can't convey in written text unless you specifically call it out.
"I made it very clear via hyperbole that it was sarcasm" Have you talked to people? Your obvious, over-the-top, hyperbolic sarcasm could just be someone's opinion taken whole cloth. In fact, you probably modeled your exaggeration AFTER a person. Can you see why, if I don't know you, there's no way to tell?
"I forgot the tag" cool, if I see the edit adding it back in, I'll revert my downvote. Consider it the opportunity cost of forgetting.
"It doesn't hurt anyone" Yes, it does. You give credence to your exaggerated position that you would never take because the people who think like that exaggerated position will point to your comment as proof that they have support. It's why 4chan rebirthed nazism.
"I still won't do it". Then have fun with the downvote. You want to make the internet worse? I'll be sure that you don't get the internet points your brain craves.
I’ve felt this on both sides. It’s no fun “giving up the joke” by tagging it, but the simple truth is sarcasm comes across poorly in text, especially when the audience is made up of strangers.
You almost always need to use the /s tag when using sarcasm in online discussions.
My preferred way around this is to spoiler the tag, since there's a few other tags of this sort floating around: /j (joking), /hj (half-joking), /srs (serious) for a few examples. Doing that still gives you a moment of not giving up the joke, but it's still ultimately there for anyone that wants or needs it
Two days ago I wrote an overly sarcastic comment but it was late at night and apparently I both made it sound too realistic and didn't put an /s - I didn't think anyone would think anyone could be that stupid.
Turns out a lot of people assumed I seriously thought that my fictional dog's vets were more likely to suggest euthanasia if they are Asian because I believed they used the corpses for meat and handed me fake ashes. I'll definitely make sure to use /s in the future now. To both avoid looking like a racist conspiracy theorist and a dog owner.