It’s probably little different to some older clauses around ‘acts of god’, terrorism, social turmoil/riots etc.
I suspect if a claim were genuine and the clause was used inappropriately that it might be deemed unreasonable by an ombudsman.
If it’s a widespread new clause, we have few options other than to be uninsured.
Others will undoubtedly have better experience, but this and linked articles may be worth reading:
There are a few things I have signed and considered that clauses might be considered unreasonable. The consumer vs business examples however seem to suggest things are stacked against us mere mortals unless I’ve misread.