Both the National Review article and this piece (https://www.indexoncensorship.org/2012/04/words-and-deeds/) by Flemming Rose credit Alan Borovoy for having been the original author of that passage (in his 1988 book When Freedoms Collide: The Case for Civil Liberties).
The New Yorker article is based on Bob Mankoff interviewing Flemming Rose and it looks like Flemming Rose may have been slightly misquoted in a way that made the attribution less clear: the bit where it says:
> In the words of a present-day civil-rights campaigner, pre-Hitler Germany had laws very much like the anti-hate laws of today, and they were enforced with some vigor. As history so painfully testifies, this type of legislation proved ineffectual on the one occasion when there was a real argument for it.
Flemming Rose is attributing both sentences - "pre-Hitler Germany had laws very much like the anti-hate laws of today, and they were enforced with some vigor" & "As history so painfully testifies, this type of legislation proved ineffectual on the one occasion when there was a real argument for it." to "a present-day civil-rights campaigner" or Alan Borovoy.