Criticizing Mozilla in every situation is almost guaranteed. An odd behavior for a community that supports FOSS.

Mozilla's credibility is a threat to the powers-that-be in the industry. I wonder if that drives a lot of it:

Attacking the messenger is a very popular tactic now. You can see it on Fox, for example. Attacking the messenger changes the topic - it makes the messenger the topic, not the undesired thing - and the messenger often responds by embracing this new topic by defending itself. The undesired thing is forgotten and to the degree it's remembered, the attack is discredited.

Because Mozilla's long term sustainability is good for the internet.

because it represents a paper thin condom that prevents Google from fucking the whole world, and if it gets steered the wrong way we're doomed until the inevitable 1990s style anti-trust suit.