When you are the target of a bully it is really hard to remember that the bully is the one who is weak and trying to bolster their belief in themselves. When a portion of your social life is in cyber-space - to find a bully there, waiting for you, must be vile. I had it at school - I would hate it in here.
What I would say to anyone who is suffering from bullying is not to wonder "would someone else feel that this is unreasonable". It isn't their call, it's yours. If YOU feel attacked - especially if it is repeated and you have made your feelings clear to the bully - then it IS bullying. We have a good system of Mods and Ops here - use them.