If this creature is attacking a planeswalker, assigning its damage as though it weren’t blocked means the damage is assigned to the planeswalker, not to the defending player.

When assigning combat damage, you choose whether you want to assign all damage to blocking creatures, or if you want to assign all of it to the defending player or planeswalker. You can’t split the damage assignment between them.

You can decide to assign damage to the defending player or planeswalker even if the blocking creature has protection from green or damage preventing effects on it.

If blocked by a creature with banding, the defending player decides whether or not the damage is assigned “as though it weren’t blocked".