There's not any particular reason why they shouldn't copy and paste this, from a technical perspective. Everyone involved has clearly accepted that they're quit

There's not any particular reason why they shouldn't copy and paste this, from a technical perspective. Everyone involved has clearly accepted that they're quite happy with SHA-1 and 1024-bit RSA being mandated as the standard for exchanging this information within the EU, and there isn't any reason why this would suddenly be more insecure now the UK isn't a member. Of course, politically speaking there are obvious reasons why journalists at organisations like the BBC would kick up more of a fuss about this as part of the Brexit deal than as an EU rule, and indeed conspiciously neglect to mention the EU is presumably already using this insecure cryptograpy internally. Writing the article in this misleading way plays nicely into existing anti-Brexit narratives about it being an incompetent attempt to return the UK to the past and about Brexiters screwing things up by not listening to experts. That doesn't make requiring every EU state to upgrade their systems at the last minute any more practical though.