CC NC forbids using the material for commercial purposes [1]. On 'use', opensource.com defers to the four freedoms [2], which includes the freedom to use software for whatever you like. So by opensource.com, software licensed under CC BY-NC-SA 4.0 is not open source. Also they don't mention creative commons when discussing open source licenses [5] because it doesn't make sense for code.
I can see why you might think opensource.com says that open source "literally means the source is public" if you only read the first sentence in their defining article [3]. Fair enough, this is a common misunderstanding [4].