PopupMenu section header size is untrustworthy

Why, oh why, does HeaderItemComponent (for PopupMenu) call getIdealPopupMenuItemSize() and then just blatantly add two offsets to the result?

void getIdealSize (int& idealWidth, int& idealHeight) override
{
    getLookAndFeel().getIdealPopupMenuItemSize (getName(), false, -1, idealWidth, idealHeight);
    idealHeight += idealHeight / 2;
    idealWidth += idealWidth / 4;
}

I’d like to have full control over the size of my popup menu section headers. Can we please move this behaviour into a LookAndFeel call?