It’s not an ACLU “demand,” it’s actually DC law. True, the ACLU of DC
supported and encouraged adoption of that law, but the wider District
of Columbia community as represented by its city council agreed with us.
And that law is not absolute; in its full form it says that:
officers may record First Amendment assemblies for the purpose of
documenting violations of law and police actions, as an aid to future
coordination and deployment of law enforcement units, and for training
purposes; provided, that recording First Amendment assemblies shall not
be conducted for the purpose of identifying and recording the presence
of individual participants who are not engaged in unlawful conduct.