So, curious.... exactly what WILL it hurt by starting the tires turning in 1st before going to second? Is it the gear change unloaded? (Explain this to me like I'm the village idiot)

My car is a low 12-second street car with a TF-2 kit. I pretty much shift it manually all the time though. The way I understand it, by engaging 1st gear manually, I am applying the low gear band. It seems that this would only make things stronger... (????). Why is this not true?