They did some talk about it when they introduced the 'use Kotlin style guide' setting for formatting.
As the default IntelliJ style preceded the Kotlin coding conventions, they didn't want teams to be confused that were using the defaults, and then did a new install, or started a new project, and all of a sudden, the formatting is different.
But I agree. I think it would have been better to do the inverse. Make the coding convention the default, and have the 'old IntelliJ default' be in the 'use from...' options.