Well, there's "okay" in the legal/contractual sense and there's "okay" in the customer-friendly, long term interests of the company. This move may be the former, but not the later, and MS seems to be banking on gaining more revenue for these licenses & switches to Azure than they lose when some customers decide to stick with AWS but move away from Windows. Either way, some group of customers, however small, will choose to move away from Windows, so their long term market share will be smaller. Is this "okay"? Depends on which way MS has placed its bets.