It's not intended that the mobs continue attacking a downed player. Typically, they should stop after the player is bleeding, and find another target (or stand around for a while before returning to their patrols/spawn locations).
There are a few scenarios where they may still attack a downed player, though. One is lag; A small spike of lag might stop the monsters' AIs from updating in time. Another is if another monster had just attacked you, or cast a spell at you - this attack may still succeed even if the monster would stop attacking you after it. Finally, it could be possible that the monster had an action, such as a special ability, queued on you and due to some mistake this didn't get cancelled appropriately. That might be the case here, though I haven't looked into the specific scripts that handle attack cancellation against downed targets.
Normally you should be left in a bleeding state. There's no need to be snarky about it.
