Machine learning is a subset of AI, just as large language models are. They’re referring to text input machine learning as generative AI here:

Amazon is using generative AI broadly across its internal operations, including in its fulfillment network where the technology is being deployed to assist with inventory placement, demand forecasting and the efficiency of warehouse robots, Jassy said.

It’s only considered generative based on the user input method of text or speech. If it learned solely from observation, it would be considered machine learning, and if it used algorithms to create the most efficient model of itself, it would be considered deep learning. They’re all forms of AI though.