1. When did I say that Amazon replaced Oracle with MySQL? I just said that MySQL is an Oracle database.
2. Open Source licenses that Amazon is not violating - a 3rdparty lawyer would be able to ascertain better about the extent of legality on Amazon's changes and its contribution back to open source software than you and I do.
3. Ex-Amazon employee here. My comments are purely based on my observation - and purely my opinions. Why can't I talk a lot?