I wouldn’t presume to know if destruction of the pipeline is justified if you look at it from Russian perspective, if they are responsible, but I can volunteer a few motives why they might be:
- an attempt to introduce a force majeure factor into any future contract disagreements
- an attempt at escalating the seriousness of threats, signalling “we aren’t backing down”
- an attempt to drive a wedge between allies by implicating a sabotage behind ones backs. US vs Germany etc.
… or a little of all of the above.
One of the key strategies employed by Russia in the conflict - is a periodic display of belligerence bordering on unhingement. I think Russia being behind it fits the MO.