> Any license which restricts a user's ability to use the software how they wish is no open source license

That's the thing though. The only thing (from my naive understanding) that SSPL limits is a business (Like Amazon) from offering Elasticsearch as a service. If an organization (Like Amazon) wanted to use Elasticsearch internally (to say, power some part of their shopping platform), they are free to do so with this license.

It's essentially protecting Elastic's business model, which quite honestly, should be the bare minimum offered by any open source product.