When someone tags you with bad karma and it points back to something innocuous or unconfrontational, its just people grinding old grudges and attacking from the safety of anonymity giving them the freedom to knife you in the back constantly from the shadows and not having to justify themsleves to your face. Some people never got past the third grade childish spite phase it would seem.
I for one would like to see the whole karma thing excised as it can only serve to drive the wedges of hatred deeper and faster and reinforce the schizms that cause people to want to bail out.