Should the British Museum's director Hartwig Fischer have resigned?

As we all know, we have a scandal involving the British Museum (BM).

According to the BBC:

British Museum director Hartwig Fischer has said he will step down from his role, after treasures were stolen from the London institution.
In a statement, he said it was evident the museum "did not respond as comprehensively as it should have" when it was told about the thefts in 2021.
Mr Fischer also withdrew remarks he made earlier this week about the art dealer who first alerted museum bosses.
He said he expressed "sincere regret" over the "misjudged" comments.

Putting aside his ridiculous handling of the antiques dealer Ittai Gradel; on the one hand, this museum - possessed of priceless treasures - failed to document, log and secure them fails in the most basic standards & expectations. It suggests that management took a complacent and slapdash approach to treasures. That no serious investigation was conducted when the issues was brought to their attention is really unacceptable. 

On the other hand, the BM - like every other major museum in the world - must have had objects leaving the back door for decades. The problem is that there is only ever a tiny proportion of the items on display. The rest are in boxes, drawers, storage rooms. Some probably haven't been seen for years. It's not easy to conduct regular audits especially with limited resources and stretched budgets.