I am surprised that the medical people have not stepped in, especially with drivers not taking fluids during a race. Dehydration can cause all sorts of problems such as dizziness, lack of concentration and fainting, even in the short term.
If the weight limit has to be raised on safety grounds so be it.
The jocks get to recover after a few minutes riding, the drivers are at it for 90 minutes or so. For many years motor sport has had driver safety as a priority, this surely must be one?