This (among other reasons) is why I quit a previous job.

The head of the department would often use politics as small talk leading up to meetings while waiting for everyone to show up.

There was literally no safe way to engage in the conversation- disagree, and you paint a target on your back today, agree and have a target painted on your back tomorrow when someone else is in charge (not to mention alienating people who might currently be on your team).

No policy in the world can make up for bad management.

I think you’re right that this is one of the biggest downsides. It’s possible to feel people out by how they react if I point out discrimination in the product, and if that goes badly I might consider leaving the company before discrimination against me becomes a problem. But I would also say that most of the discrimination I’ve experienced is not really overt enough to be a good early warning system. At some point it becomes irrelevant to wonder “am I not getting promoted because I have X marginalization, or is my work actually not great, or does this person just dislike me specifically for no reason”; better, in my experience, to consider it one of life’s mysteries and try to find a new job.