That was a strange response. Back-testing gets dissed two ways,
Imo its a highly valuable beginning to any defined rule set on trading. It should include bear markets, bull markets and trading ranges. Then you move on to real time with real money.
You CAN time the market!
But only after you trash the big 3 myths.
Myth 1 - its possible to get every point of every move ...Myth 2 - you'll never have a drawdown ......Myth 3 - you'll never have a loss