Why is Java 14 not LTS?
Take look at this announcement:
For product releases after Java SE 8, Oracle will designate a release, every three years, as a Long-Term-Support (LTS) release.
This means another LTS (ver. 17) should be 3 years after Java 11, so in September 2021. Java 14, however, was released in March 2020, so no LTS.
Java 8 is LTS, but it is not a part of 3-year release cycle, which was announced long after the release of java 8.
As others have quoted, Oracle is to designate a release as LTS every 3 years. However, as I read this policy, the designated release does not need to be the last one, or even one produced during the same year. For example, the release to be designated as LTS during 2021 could be (though not very probably) Java 14 instead of 16 or 17, depending on adoption, stability, and other important factors. If this were the correct interpretation, I'd actually agree with it as it would not put the development of new features on freeze (or severe slowdown) as the end of each 3-year period approaches.
Bottom line, we'll see.