The New Zealand club have dominated Super Rugby over the past decade, winning seven titles in a row.
But under new coach Penney, brought in this season to replace All Blacks-bound Scott Robertson, the Crusaders have only one win from their opening eight games.
Chief executive Colin Mansbridge said that firing Penney, who was sacked from his previous Super Rugby coaching role with the New South Wales Waratahs in 2021, did not make sense.
"When you think logically about it, what are your options? That's not a very clever option, no matter how bad things get," he told local broadcaster Newstalk ZB.
Mansbridge said he accepted criticism from fans "because they are emotionally invested.
"But from commentators, I think it's childish, frankly.
"When you see those things happen overseas, you don't see improvements in results, that's the fact," he added.
"There'll be an exception that proves the rule, but generally it makes no difference, and in fact, probably things get worse."
