I don't get the downside of accepting the membership - unless they have you set up for automatic renewal or somesuch.
If you are a member, maybe the opportunity will arise for you to do some good with the vote?
And it may be a good thing that the NRA is involved? They may be trying to resuscitate the CRPA? If so, and you choose not to accept the membership, why not send the free membership to the NRA? Tell the NRA why you don't want to be associated with the CRPA in a venue where it might help the NRA understand what the NRA shouldn't do - and what they need to pressure the CRPA to do?
CGN's token life-long teetotaling vegetarian. Not qualified to give any legal opinion so pay attention at your own risk.