If it’s truly open source, one business shouldn’t dominate the project’s development. That’s tantamount to the project becoming shared source that accepts community contributions, not community driven open source backed by many orgs. It reinforces a monopoly in that community. And these companies themselves are not tiny victims (many IPOd at multi billions). They also tend to compete with their customers and community in the same way as AWS, so I’m not sure they can cry foul when AWS does the same.