I quite agree, and I tend to resent and resist the tag unless the sarcasm would otherwise rely on tone or delivery, in which case why write it at all.

I think the internet has spawned a nascent global culture, and while that is still taking shape we are often left feeling as if we share insufficient context with one another to form an understanding. We’ll grow together as a global culture in time I hope and trust, but in the meantime I think it’s an error to rely on low-context modes of communication. It is a crutch, and it only perpetuates the distance between us.