I like this article but I think your version of the headline on HN "Cisco copied Slack called it Spark" is too clickbaity and VB's original "Cisco doesn’t want Spark to be like Slack. Here’s why" is more appropriate.
I agree. The original is much less clickbaity.
Disclosure: I work on Cisco Spark.
Let's all pretend that Slack is unique and innovative for a moment.
I question the motives of OP in regards to the title change, sounds like someone has a bias.