Pragmatically speaking, you're right. Something needs to keep the lights on. Further, even if they did not set Google as the default search engine, surely many users would configure Firefox as such.
The browser isn't compromised, but their principles are. When you compromise your principles or apply them very selectively, you lose credibility and authenticity.
A fitting example of this is their Facebook container. They have poured a lot of resources into minimizing the potential harm Facebook can do to its users. They totally can, as they have no dependency on Facebook at all. Yet no similar effort is made to isolate Google services.
Again, we know why. Most users are unlikely to care, but it demonstrates that principles are for sale. If we were to focus on privacy only, both Brave and Apple take a far more principled approach in protecting privacy consistently. So where does this leave Mozilla on this matter?
Brave is basically the result of the firing of Brendan Eich, for his private donation to a cause rejecting gay marriage. You can think of that what you want, but there is zero evidence of him ever projecting this private belief in the workplace in any way harmful to anybody at all.
But I get it, it looks bad for a progressive organization like Mozilla. A PR disaster.
Their progressive image indeed largely seems PR. For example, they've had a series of large layoff rounds, whilst at the same time drastically increasing executive compensation. You have to wonder where this compensation is based on, as leadership is running Mozilla into the ground. Market share keeps bleeding and there's zero alternative successful revenue streams.
That's classic neoliberalism. Firing workers whilst enriching yourself. At the same time, they are involved in "equity" projects to address the issue of some people unable to afford internet access.
This is all very confusing. Principles are sold out, contradicted, and only seem to apply to others. That's why to me, Mozilla's "values" have little value.
A Firefox user does not need to care about any of this, but here comes the problem: Mozilla is downscaling on Firefox engineering whilst increasing their more activist/political projects.
How is that strategy not a disaster? They're great at engineering yet terrible at activism.