Ah. So there are two types of investors: some are self-admitting market timers, and the remaining ones are hiding behind their "rebalance" personal strategies.
Actually, why are market timers called "dirty"? Is it because they most often fail in their Quixotic quest and lose their shirts?
However, the market timer, if successful, does a lot of good. He not only adds to his fortune, but also acts as a market stabilizing force. By selling high and buying low, he provides liquidity and reduces the market wild swings. His actions counter the madness of the crowd who flocks into the market en-masse in good years, and liquidates stocks in downturns. A very noble act indeed!
The successful ones are revered as heroic and wise contrarians, while the failing ones are called "dirty".
So, don't fail, damn it!