I think y’all overthinking this. Red = Cool, unique, and a visual contrast against Rey’s blue saber. That’s all it needs to be.
But if we have to get technical, I guess you could say stealing force power channels the deepest depths of the force and this is even more dangerous than standard lightning. It’s something on a scale we haven’t seen since the Son (or for most fans, ever).
Actually… this would explain why Palps can suddenly force blast an entire fleet…