Is the Task of HRM Professionals to Advocate For Employees?

What do you think of this claim by an American “strategic HR lawyer”, which came to me by way of a Tweet yesterday?

Speak Up!

No one will advocate for employees as well as the HR professional. This is one of the areas in which you can shine.
When employees are being treated poorly, open your mouth.
When an employee is being unnecessarily favored, open your mouth.
When a decision is being made by management that adversely affects an employee or a group of employees, step up and open your mouth.
All human resources professionals want to have the opportunity to sit at the table as a member of senior management. If you do, don’t be like some of the others and shy away from advocating for employees because you think that you have to come across as a business person. It is your job to have the employees’ backs. Be proud and stand up for them.

Is it the job of HRM professionals to advocate in the Boardroom on behalf of employees?
Should HRM professionals argue strongly against layoffs and for better wages and benefits for employees? Should HRM resist the trend towards part-time, precarious, and ‘self-employment’, and argue instead that employers should retain full-time standard employment?  Should HRM insist that employers have a good reason for firing someone?  Should they demand a neutral arbitration process to test whether employees have been treated fairly and in accordance with their employment contracts?  Should the HRM profession advocate the government for stronger employment laws to protect vulnerable workers?
I’ve discussed this issue before, including when I noted the OECD’s conclusion that rising inequality of income in Canada is due in large part to the shift towards ‘flexible’ employment arrangements and away from better paying, more secure full-time employment.  I asked then what role HRM has in fighting for the maintenance of good paying full-time jobs, as opposed to being the people who implement the shift to non-standard work that the OECD says is harmful to workers. Some self-professed HRM professionals commented in response to that blog entry that HRM’s role is to support “the business”, and not to advocate for employees.
But if it is not the role of HRM to advocate on behalf of employee interests, then who should play that role? An obvious answer is unions, yet the HRM profession also argues vehemently that it is the role of HRM to prevent their employees from unionizing.  That’s why the Human Resources Professionals Association offers regular seminars on the dire need for employers to be proactive in discouraging employees from looking for union assistance.  Here is what their 201o flyer proclaimed:

If you are union-free, you should try to stay that way. This is not a matter of magic, legal trickery or blind luck. It takes consistent and effective management practiced day-in and day-out, based on a long-term plan. The union only has to succeed once. To remain union-free, management has to succeed every single day, forever and always.

So, which is it then?  Is HRM’s role to be a strong advocate for employees, even to the point of challenging the ‘business’ people in the Boardroom when decisions would be harmful to employees, as the American lawyer argues (above)?
Or is the role of HRM to just implement business decisions, even if (as if often the case) those decisions are not beneficial to workers?
If it is the latter, then is it disingenuous for the HRM profession to claim that the employees do not need the assistance of unions?