What you're suggesting is illegal. They cannot treat citizens with different parentage differently as it would create multiple classes of citizens. Also, there is no evidence that PR sponsors are being prioritized over citizens. Outland applications are prioritized for family reunification purposes regardless of whether the sponsor is a citizen or PR. Don't compare your inland application to outland timelines.
I am not aware of any evidence that a specific group of people is abusing the PR sponsorship system just to get US visas.
Of course it is illegal. The law needs to change... the system needs to change. But by your very own words "Outland applications are prioritized", so there already is a class system.
Trudeau has destroyed this country with unchecked immigration (mostly from india) when a taxpaying citizen who was born here, and who's parents were born here, has to sit backseat to new PRs.
You are not aware because you are not part of the indian community. I am, and this is common knowledge in the community. Indians with an education have no affinity or interest in Canada and want to go to the US.
To add, I expect fully that at the next USMCA discussions people born in India will very likely be put on a restricted list for TN or L1 visas, BY REQUEST of the Liberal Government. At which point immigration to Canada from India will drop drastically. There are lots of links online but you can see a quora page here which describes the scams and abuse
https://www.quora.com/Has-any-IT-professional-Indian-by-birth-successfully-moved-back-from-Canada-to-the-USA-in-TN-visa-in-2021-post-Trump-How-is-the-job-search-and-visa-related-from-companies-and-USCIS-experience
Just search "indian TN to Greencard via Canada" and there are thousands of articles. Or just ask newly minted indian PRs in Canada what their plan is.
Come to Canada somehow. > Get PR > Sponsor spouse > Spouse arrives > Get citizenship > Get TN job in US (fake or real) > move to US with spouse > have child in US > Child is US citizen > petition for H1B or Greencard
Then they plan to retire in Canada or buy rental properties in Canada with American income, and also cross over for non US-covered medical services, or if they are scamming the system by having a fake TN job in the US they use Canadian medical.