Applying for a warrant through a legal process is absolutely not the same as requesting data from a tech company (especially because Amazon has incentive to cooperate with police in order to continue to sell these cameras)
Because they have written Law Enforcement Guidelines that are pretty clear and otherwise as a lawyer I know they don't just turn over customer data and information without a written order (and even then, they may object and fight it in court).
Why do you believe they are just turning over consumer data/info/video without any court order (besides, police are customers and Amazon wants to keep customers happy)?