Because Oracle is Oracle, the most evil company in tech, the one most blatantly greedy. Look at what they pulled with Google. Oracle would wait till the tech usage grows and then use patents and API copyrights or whatever else they invent out of thin air to go after the players using its tech. The free license of Graal does not protect you from that, GPL2 specifically not. See https://www.gnu.org/licenses/rms-why-gplv3.en.html.
Google abused Sun, took advantage that they were in a critical financial situation not able to sue, and when they crashed, did not move a finger to rescue the company assets.
Now Android has Google's own J++, limiting what kind of Java libraries are portable to the platform.
At the same time, some OEMs are adopting Android instead of Embedded Java, thus increasing the fragmentation about what Java libraries are actually portable.
Google just though they could let Sun close doors and get away with how they created their own J++.
Also doesn't change the fact that even with Android 8.1, I as Java developer cannot take a random jar from Maven Central and be certain it won't crash and burn on Android, regardless of the version.
But I don't see how you can tolerate that contradiction. Either you agree with Oracle that the Java APIs were copyrighted and Google should not have been allowed to reconstruct them. Or you worry about fragmentation coming from an incompatible Java implementation. Doing both is nonsensical.
FYI, what you've linked to is a breakdown for the licenses of various projects comprising GraalVM. The licenses you listed only apply apply to TruffleRuby.
Having said that, Graal and its related projects are all open source, with a license listing available in its README: