I took her post as she also has had beef with the SIL. I've been there myself with both my SILs and my MIL. During that time I probably called them worse things than unattractive. Sometimes a person just needs to vent and it may take a form that doesn't seem relevant to the issue, but I completely can understand why.
Or, maybe it is relevant in that she's using unattractive to mean her SIL doesn't have any hair, doesn't know how to grow/care for hair, and therefore shouldn't be messing with her daughter's hair. JUST KIDDING! lol