if it's free, you're not the customer, you're the product
Does this apply to Linux and other open source software?
That is an excellent observation/comment.
I think the answer there is "it depends".
There's an intentional component behind any action, and that is an important factor.
I think your observation may apply to Canonical, though you'd be better off asking someone who knows more about them, e.g. 40hz.
For a lot of other FLOSS software, I'd say no. The motivations there are not commercial and there is no real commercial component.
It also applies to some non-GNU GPL licenses, e.g. Mozilla, Apache, BSD, WTFPL, etc. I think most of those kinds of licenses are not conducive to the type of exploitation that you find in the "free as in no money" free software/service world, e.g. Facebook, etc.
You can commercialize even public domain materials. This is in part what Aaron Swartz was up to - taking public domain materials back to the public.
So, it's not like there's anything that isn't open to abuse - anything can be turned to a negative purpose. Some things are simply more prone to abuse than others, e.g. When was the last time you heard about anyone abusing baking soda or dish washing liquid?