The corporation is governed by the same rules as the foundation, compare https://www.mozilla.org/en-US/foundation/
> Our work is guided by the Mozilla Manifesto.
to https://www.mozilla.org/en-US/foundation/moco/
> The Mozilla Corporation is guided by the principles of the Mozilla Manifesto.
(I'm an employee of moco, I've always felt like I'm working at a values-based rather than a profit-based organization, personally.)
Just to clarify, since this sentence was ambiguous: not-for-profit companies do not have shareholders or owners. So the fact that there is no "pressure from shareholders" is vacuously true, because there are no shareholders.
Not-for-profits typically have donors and boards of directors, who both apply pressure to see the corporation's funds used to realize its mission.
I'm board member of smallish Czech non-profit and one of the things I've found out is that the legal requirements on the corporate governance structure are mostly equivalent to what is required for publicly tradeable corporation that is actually not publicly traded, thus for me it makes some sense to equate voting members to shareholders.
The goals and the incentives are very different.