Because Royal Honours are awarded by the Sovereign in an exercise of prerogative power, the process should be free as possible of litigiousness, recrimination and inappropriate comparison. The procedures and conventions should be such as to minimise debate as to whether or not any particular person should have received a Royal honour, or whether or not the kind or level of an honour actually granted was appropriate.
Or, in plain language, "no-one should ever question an honour, ever, because no-one should question a decision of the monarch, ever". Its so very seventeenth century, isn't it?
Except they're not "awarded by the Sovereign in an exercise of prerogative power". They're awarded on the advice of Ministers. And the next effect of this decision is to shield the decisions of those Ministers from any form of accountability. And when Ministers regularly award honours to people who have made generous donations to their party, that simply invites corruption.
But suppose we take the Ombudsman's decision seriously. Isn't the clear implication then that if we want a clean society where Ministers are accountable for their decisions, we need to dissolve the monarchy and become a republic?