Fogs on during high beam, destroys the function of fogs! The lights hit the moisture particles and are reflected back at you.
If you are in an actual driving situation with reduced visibility as a result of fog or even heavy rain/snow this is absolutely true. But, there can be benefit to doing so, it all depends upon the situation. Its not clear to me the OP's intended use. I can agree that running fog lamps with the high beams at road speed has no value, and actual impairs vision, even under clear conditions, IMHO (since the flood of light directly in front of the car reduces the driver's visual acuity for long distance viewing, which is presumably needed when the high beams are selected).
However, that being said, if the OP's interest if for low speed driving on unpaved or unimproved roads, using all lighting sources to 'flood' the area in front of the car with light has its benefits, but you don't have a need for long range visibility in this situation either.
What it comes down to is the driver knowing when its beneficial and when its not, and it seems perfectly acceptable to want to have the CHOICE
of how to control the vehicle's lighting, instead of it being dictated by some design choice, or nanny laws seeking to protect us from ourselves..
If anything, good fogs can be used with no low beams!
Which supports my point above, because the original factory configuration will not allow this either..