If private companies can hold copyrights on portions of the law, that inhibits access to those laws, and I think any reasonable person would agree that citizens have a basic right to access the text of laws and legally binding regulations, and paywalls or other restrictions conflict with that right.
But if the government can essentially revoke a private individual or company's copyright merely by incorporating otherwise protected text into legislation, that can have adverse effects on copyright holders.
And it would be interesting to see just how far you could stretch a claim on both sides.
For instance, let's say that a law specifies that vehicles used by some governmental department must be maintained according to the specifications in their respective owners' manuals. Could that be argued to be a type of "incorporation by reference" of the specifications, thus voiding the copyright of the owners' manuals?
Or what if a private company tried to impose absurd restrictions on accessing copyrighted material that has been incorporated by reference, such that even the governmental agencies charged with enforcing the law were unable to access it? Could that be a way of subverting the law?
Or what if a lawmaker has it out for a particular publisher or writer, and purposefully quotes their copyrighted texts (beyond what would typically be considered fair use) in legislation as a way of damaging their copyright?
And if it is the case that nonprofit groups that devise standards for public safety and device interoperability are deprived of their copyrights because those standards are incorporated into legislation, I would imagine it would disincentivize the work they do, perhaps leading to less well thought out public safety and device interoperability standards.