I have the same “problem”:
It seems really a big workaround to change all light channel on all lights (or on all static meshes, both would work) for just want to ignore 1 mesh of 1 light. Also could produce a bug, when your forget to switch on 2nd light channel on a light.
If somebody knows at least a way to configure this globally, perhaps 2nd light channel as default on all existing and all future lights, would be nice to know.
Also would be nice to know if this have a notable performance impact.