>> What is the relevance of funding your competitor?
> That's not an argument.
Sure it is. It's a great argument. Do you somehow think Amazon is limiting itself to copying businesses on the AWS platform only? No: they'll copy any successful business anywhere.
Unless your business is Netflix, you, by yourself, are not contributing enough to their bottom line to boost their efforts to compete with you. And guess what: Netflix doesn't believe that the money they're paying AWS is enough to hurt their competitiveness with Prime Video. The 10 VMs your company is going to run aren't going to matter.
You can certainly object to Amazon business practices and take a principled stand against doing AWS business with them, but that's something you would presumably do whether or not they were competing with you.
More concerning would probably be the possibility that your AWS service would be suspended or otherwise purposefully disrupted.