Even if some random kafka committer that you can't source believes that, the reasoning doesn't add up:
SBT makes it fairly straightforward to cross publish for different dot releases of Scala, and libraries in the Scala ecosystem do it all the time.
Scala dot releases are far apart. It's been over 2 years since 2.11, and 2.10 released in 2012.
By contrast, the JAVA client that the Kafka project published in November is already undergoing breaking changes for the current release candidate. It's pretty clear that avoiding breaking changes is not an overriding concern for them, and even if it is, it's equally clear that Scala was not the inherent problem.
