Well no, because the /s tag isn’t symmetrical.

In cases where the /s tag is used instead of sarcasm being interpreted successfully, there’s no mechanism to determine how well bonded and ready for complex communication a group is.

It’s similar to banter, where one insults one’s friends in good fun. It’s a readiness test. The guy who gets insulted by your banter isn’t ready to communicate at a complex level with you.

Same for people who can’t figure out when you’re being sarcastic.

Misinterpretation of sarcasm is a canary in the coal mine, an indicator that complex topics aren’t going to be successfully discussed here, because there’s too much misinterpretation happening.

It's not that the point is ruined. It's that it's no longer sarcasm. The whole point of sarcasm is that it seems like the message is genuine. Ironically, using /s makes a statement unsarcastic.