I haven't wrote that the government said that. But a lot of online commentators and even some news outlets immediately started to discuss "cyberattacks" (including the linked article) and asking "maybe it was the Russians?".
Most people who are familiar with how electric grids operate are in agreement that high degree of renewable generation has likely made the situation worse not better. We know that right before the blackout the grid had a sudden dip in frequency, which is exactly the condition which leads to unstable work of inverters used by renewable plants. Just watch this Practical Engineering video [1], if you are not familiar with the topic. It discusses exactly the problems I wrote about. So renewables may have not been the direct reason for the blackout, but they are highly likely have helped to tip the gird behind the critical point.
A lot of news outlets were not part of the left leaning side of the goverment; the theory for an attack was set from every media, from the Basque/Catalan left and right to the pro-Spain left and right.
In fact, you are doing exactly the thing they have avoided so far: Jumping to premature conclusions.