First of all, I don't think constructive criticism and frank incivility belong in the same bucket. One is a good thing about us. The other is a negative.
However, if we want to restore our tribal integrity, we can't let management play us against each other so easily. There are so many conflicts that look technical but are actually cases where management deliberately played tech people against each other (usually, to create a sense of competition on work hours, dedication, et al). Most engineers lack the social skills to perceive when this is happening.
One thing about business people: they constantly talk each other up. Even if they don't like each other, they say good things about one another. It's game theory. They know the difference between luke-warm and real praise, but everyone else thinks The Manager is in good standing (and therefore stays in line). They get themselves to a state where not saying something positive about someone is a damnation. They can dog-whistle by criticizing a member of their tribe within it, but in a way that outsiders don't recognize, allowing them to keep a unified front.
On our over-honesty, there's one case I know about where an engineer was leapfrog promoted to top management and had a lot of non-engineering reports. They had a performance review system where 5 (out of 9) was nominally average, but everyone came in between 7.5 and 9.0. He gave a lot of 6's and 7's thinking he was giving honest ratings (because no one looked at the perf numbers for IT, reviews he'd written in the past had no effect) but it ended up making a huge mess when HR wanted to put two-thirds of his team on PIPs. He reacted by changing everyone's rating to a 9.0 and giving honest feedback verbally, which is how it should be done.
I feel like we need a similar "understanding" with each other. To other engineers and technologists, we give blunt and honest feedback. But we need to stop the cannibalism. To management and HR, we take a strict attitude of praising other engineers (whether we think they deserve it or not). We should never narc each other out.