Isn't that exactly what Obama was trying for? I've never read any statements from the Obama administration that makes it seem like they find anything about this case justified or acceptable.
This quote by a spokesperson in the article supports that:
“Chelsea Manning is somebody who went through the military criminal justice process, was exposed to due process, was found guilty, was sentenced for her crimes, and she acknowledged wrongdoing,”
A criminal that's being granted a shorter sentence, not the "support" for someones actions a pardon would be.