The Mozilla Foundation is a non-profit organization.

The vast majority of people working on Firefox are employees of the Mozilla Corporation which is a for profit subsidiary of the Foundation.

https://www.mozilla.org/en-US/about/governance/organizations...

the foundation owns the corporation and can dissolve it if it turns evil. There's no similar public-good outfit that can dissolve Google.

That has not bearing upon whether the Mozilla Corporation is for profit or not. It is for profit and the original statement was regarding a lack of understanding why someone would use a browser made by a for profit company. Firefox is factually made by a for profit company. One whose major source of income is the nefarious Google.

I'm also afraid how this usually turns out is the for-profit part takes over the non-profit part. See OpenAI or just about any major national non-profit in the US.

No, this effectively means that the corporation can do evil and will always point to its owner being non-profit as a justification for doing more evil. The corpo gets a "kind face" behind which it can do dirty deeds.

Inclusion of Pocket in Firefox is a representative example - included despite overwhelming community objections for more profit!