Just to add another view here: I'm currently a Data Scientist at Capital One and enjoy it quite a bit. I've found management to be open, supportive, and invested in my and my coworkers' success and development. They also allow and encourage people to change teams within the company, so if you find yourself in a situation that's not working out, you can move to another team.
I've also not seen anybody leave the company on bad terms. Of course I'm sure that happens, and I'm sure there are bad managers here as everywhere. I'm sorry that you had such a negative experience.
I used to work for Capital One Europe, the UK side of the business that currently only does credit cards, until last year. I'd seen a mixture of some people leaving on good terms and some on bad terms, with no obvious correlation to performance. Personally, I left on good terms for a new role elsewhere.
I'd suggest when you're talking about a company of sufficient size; there are always going to be a mixture of those leaving on good terms and those not.
The company culture tries to go in a good direction, but it fails at the individual manager level. From people I have talked to, this is not just me but widespread, especially financial services in Plano, Tx.
I get yelled at on a weekly basis. Belittling is comon too, such as being told "you're not that smart and this isn't rocket science". Managers are non technical managing a technical project and micromanagement is the norm.
I've also not seen anybody leave the company on bad terms. Of course I'm sure that happens, and I'm sure there are bad managers here as everywhere. I'm sorry that you had such a negative experience.