I don't think it's a challenge at all. It's not my position, nor does my position hinge on it. Elastic is merely an important contributor to ElasticSearch, but they should not be regarded as "hostile toward open source" (esp not moreso than Amazon) because--in existential self-defense--they began writing nominally proprietary features (which they give away for free to everyone except their competitors).

Most of Elastic's critics in this thread seem to believe that, as the primary sponsor of the project, everything Elastic does must be open source (apparently) at all costs or they are somehow anti-open-source or otherwise "worse for open source" than Amazon.