Yes, paragraph 179(b) is highly problematic. With the dual intent purposes, basically if there is a sponsorship application, that's viewed negatively, and it's a factor that's viewed towards refusing a TRV application.
Requiring spousal sponsorship applicants to additionally apply for a TRV adds another layer of expense and processing for them while they're being processed for their spousal sponsorship. It adds another layer of expense for government processing. It's an additional application that wastes government resources, knowing that the applicant is going to be staying in Canada permanently once their permanent residence application is completed.
I completely agree that 179(b) is very problematic. Showing dual intent is very problematic for visa-required individuals who are being sponsored to Canada.