I have to agree. That's only part of the letter that is incorrect. Who dictates who rides the jumpseat is not the CA on a macro level. It actually involves the DHS, the Department of Transportation, the FAA, the company, and finally down to a micro level of the CA. The company has a Macro control at its level as well and can dictate the use over the CA.
Here's an example of how it's NOT the CA's seat until someone requesting a ride has cleared all the other agencies control and policies, and is literally asking the CA for a ride. Remember after 9/11.....who controlled the "non use" of the JS and made commuting and travel another nightmare during those times? Answer: It was not a Captain, and not one CA controlled the seat on "their" plane during those times.
This is why APA will never control the jumpseat or its use no matter how many resolutions they pass. I like the letter and agree there is a better way to award the seat, but in the end, it's a policy