Is subject to case by case, really.
Let me ask you this - you are in a trader convoy and you counter-tag. You have absolutely no desire to fight. Is it griefing ?
You make a bad tag ( ow translation can sometimes place you in the wrong spot ). Is it griefing ?
You are an advance scout frigate for the "home fleet". You manage to tag the slower rear-guard of the enemy fleet with the intentions of keeping them in combat until the bulk of the fleet arrives ( and hope the enemy fleet turns back to engage ). Is it griefing ?
Take a good look to your gameplay after you logoff, what went wrong, what you did good, where did you "subvert" the intended gameplay to suit you ? What did the enemy do to suit them ? What makes it different ?