At least as per the wikipedia page[1], there is a lag of 2 years between product and company, and there prior history of him working on similar products. So I think it is reasonable to give benefit of the doubt that open source product was created in good faith and commercial interests only got explored later.

Most open source to commercial success stories like Kafka, Mongodb, and Elastic do seem to follow similar path.

[1] https://en.wikipedia.org/wiki/Elasticsearch#History