Iiuc, they are basically using open core model, with core app being free/open/libre under Apache license, and extensions proprietary with code available non-free/non-open/non-libre Elastic license. At least to me the situation seems pretty clear, and Amazon complaining that they can't take all of the code to create a competing service seems pretty disingenious to me. OP's post is thus in line with what I would expect - but it seems to irk you in some way. What is it that I'm missing?
I said more here[1] but basically the use of "open" around their gratis/proprietary code. Never "open source" so it's not an untruth but it's still misleading especially in a context where they're also talking about their contributions to open source, a commitment to being open, etc.
