I'm happy to answer both of those questions.
Your first question is about why these changes are being done legislatively. It is true that many of the mechanisms, but not all of them, could be done through program or policy or other tools. Enshrining the requirement in legislation, of course, brings additional gravitas and enforceability to them for those who will be charged with actually enforcing them.
One change that is not possible to do through program or policy is the amendment to the preference.
Let me just go back and state that for the things that are possible to do through program or policy, qualification standards now are currently reviewed for bias or barrier. This is adding an extra layer of having a legislative requirement.
In terms of the citizenship preference, there is no official or legislative impediment to permanent residents' being hired in the public service. The challenge is the mechanism through which an appointment is actually made. The legislation contains a preference for external, advertised appointments, so these are positions that would be posted for anyone, broadly, to apply. For someone who might already be internal or for a position that is not widely advertised, there is currently no block on a permanent resident's being appointed to those positions.
For these external advertised positions, however, the legislation states that there is a preference for Canadian citizens. That doesn't mean that permanent residents are prevented from applying; it doesn't mean that they're prevented from being considered. It means, however, that when the hiring manager assesses all of the essential criteria, if they have a permanent resident and a Canadian citizen who both meet the essential criteria, the Canadian citizen must be hired, given the preference over the permanent resident.
What the amendment would do is add the preference to the permanent resident. The Canadian citizen and the permanent resident would then have the equal chance of being hired, if they both met the essential criteria. The expectation is that this would reduce a barrier for some who are otherwise qualified to work for the public service.
Of course, those external, advertised appointments are really a key foot in the door for many people to join the public service.