The deal was that MS was going to give them billions in exchange for 49% of the for-profit entity. They were also reportedly waiving the azure bill since their interests are aligned.
MS is saying that if we give you 10 billion dollars and don’t charge you for azure, then there are some obvious strings attached.
OpenAI is presumably free to do what the rest of the players in this space are doing and pay for their Azure resources if they don’t want to play nice with their business partners.