i fell into a managerial position once, and i was the lovey-dovey wanting everybody to be happy type. i was bad at it, but there were two major factors that lead me down that path:

1) I didn't want to be a manager and it was the path of least resistance

2) the company that was large and stable enough where getting peak-performance out of everybody wasn't necessary to keep things going smoothly

  2b) the company had so many layers of beureaucracy, that actually getting peak performance wouldn't have actually improved anything

+1 to this.

I'm currently almost 6 years into my dream job (20+ years career). My manager maintains a culture/atmosphere where belittling people, yelling, or any sort of overly negative actions towards someone, especially in public, is not allowed. This may seem very lovey-dovey but it does also mean newer engineers or more junior ones aren't afraid to ask questions or even question existing ideas. Asshole behaviors are often used to maintain the status quo and stop people from ever questioning how things are done.

In addition, she encourages frequent, timely feedback that are objective, not personal, and, above all, she is actually rather quick to fire under-performers.

This is easily the most productive engineering team I have ever been on. A team can have both high standards and have high psychological safety. I think that's just good professional behavior -- there is never a good reason to get personal or publicly humiliate someone.

How does feeling psychologically safe work when the boss is quick to fire "underperformers"?

That's totally a real question because I have trouble imagining this.

Is it the kind of situation where everyone involved, including the person in question, knows they're not up to the task?

That's exactly it. She (and other managers on our engineering team) doesn't fire arbitrarily or on a whim. That's not what I meant by quick. The management culture is to always give frequent and timely feedback so that the person knows how they are performing -- be it good or bad. By the time they are fired, it's pretty obvious to them (and likely everyone else) that they're underperforming. It should never be a surprise to that person when it happens (or when the opposite happens such as when someone is promoted)

I think your question is a really good one and really gets to the nuances of having both a high performing team and psychologically safe place. It's much easier said than done and requires good, consistent management habits.

Sounds like a great manager. Though I'm pretty shocked to see a disclaimer that avoiding belittling or yelling at coworkers at all could be considered "lovey-dovey". I've only seen that type of behavior at one company I worked with briefly, have I just been lucky/careful?

I may be the odd one here but my career consisted of finance and software engineering. Until my current job, there was always screaming and yelling at all my previous positions that I just assumed that was the norm. It’s more likely that I’m just extraordinarily unlucky because as you’ve noted, not screaming or belittling colleagues is the norm in much of society. I think my issue was that I’ve experienced it so much that I just accepted, especially since I saw it happen at my very first job.