Well yes, unless you're in a unionized environment, an employer can pretty much fire anyone, for anything, at any time, unless there are laws specifically prohibiting it, such as discrimination laws, which are hard to enforce. It really comes down to how much they have to pay to make you go away quietly. Most provinces / states have minimum notice / severence provisions unless they're claiming they fired you for cause, which is really hard to prove.

I'll use my case as an example. I got fired at the end of June. No cause. The reason I was given was simply that the managing director wanted me gone. The managing director hated the fact that I worked flex time, to accomodate addictions treatment. I couldn't claim discrimination though, since nobody knew why I worked flex time, it was just something I'd negotiated when I started. Anyway they offered me the minimum spelt out in my contract, 4 weeks pay in lieu of notice (ON's statuatory min. is 2 weeks/ per year) and two month's severence, one month for each year I'd worked there. 3 months isn't a lot of time to find a job. I however knew the details of every severance package that had been paid out, as I administered them, so I went back with a counter demand, basically saying they had no cause for firing me, that they admitted it wasn't performance related and what they were offering wasn't consistent with what they'd given othe employees.

In the end I got the 4 week's pay in lieu of notice, 5 months severence, 6 months of benefit continuation, 1/2 my annual bonus and $2k for outplacement services of my choosing. And I'd only been with the company for 2 years.

Employers count on employees not knowing their rights and not standing up for themselves. You've got a discrimination complaint, make them pay to get rid of you.