It sounds like you are confusing the multiple attacks described in the article. The most recent attack in August 2017, the primary focus of the article, was indeed intended to manipulate controls and cause an explosion. The January 2017 attack, part of a string of them, is what you are describing. That one was not suspected of intending physical destruction but, "to inflict lasting damage on the petrochemical companies and send a political message."
The article is the one muddling the various attacks. It gives the impression of campaign of multiple attempts at murder, when in fact we have a plurality of attack intents, evidence imho of very different attackers.
