I think most people who use it are just scared from the uneducated downvotes/ backlash and I think it just ruins the sarcasm.
I started to avoid using it on other social media as it seems kind of dumb.
My opinion for it on Lemmy is mostly the same but it might work better here if Lemmy had a sarcasm tag instead(the same way NSFW tag work)of /s to signal the sarcasm instead.
You can be as bitter about it as you like but it absolutely is required. You could come up the most obvious sarcasm you could ever imagine, and I’ll find you people that believe you’re being sincere.
We live in the post satire era.
I’m not sure how your idea for a sarcasm tag is any different to /s, it seems to be a roundabout way to achieve the exact same thing.
https://en.wikipedia.org/wiki/Poe’s_law