On the one hand, the US explicitly, publicly, and repeatedly threatened to unilaterally stop the pipeline if Russia invaded Ukraine. The US has a clear benefit in the sense that they remove the option for European allies to buy Russian oil. The US also has the ability to do it in the form of ships in the area.
On the other hand, perhaps it's in Putin's interest to destroy his own pipelines for some reason.
The key point is that "they" is the Ukrainian war propaganda machine, which is obviously not a reliable source of news or analysis.
It is also a classic propaganda technique to differenciate between the awful dictator and its poor people/country.
I do not know what happened and if it was deliberate it is not obvious who did it. People should be prudent and not buy into propaganda from either side.
"They" specifically referred to /u/yznovyak here, I don't know if they're part of a war propaganda machine or not. But /u/yznovyak talked about what's in Putin's interest, /u/mytailorisrich argued that no, it's not in Russia's interest. All I was doing was pointing out that /u/yznovyak was talking about Putin's interest, which might not perfectly overlap with Russia's.
And you're right, pointing out that there's a difference between a dictator and their country is a common propaganda technique. But it's also just true, and if it's not part of your analysis you're probably doing it wrong.
And to be clear, I'm not arguing in favor of either side, I don't have any clue who did this and I'm not trying to pretend I do.
The person I was replying to wrote "Common theme I've heard here (Kyiv, Ukraine)". They (Ukraine) are at war so everything in their media or stated by government and President is part of their war propaganda machine. That's how war works.
The West is effectively part of the war so we cannot trust anything we're told there, either.
The only thing we can do is think for ourselves.
Oh and I've just realised that my initial comment has been flagged! You could not make this up... Very disappointing.
I wonder what would be the bare minimum required to stage an operation like this, if one were willing to take big risks. Like, combat divers operating from an inconspicuous sailing yacht or the like? Sail into position, go down (80 meters should be doable with Trimix), place explosives with timed fuses (set to a few weeks?), go back up, throw the equipment overboard later, sail into Kiel with no one the wiser? Not that such a scenario is very likely, but there have been a lot of crazy stunts in this and other wars.
I'm certain that there will be investigations from NATO navies soon, and we will have some explanation. Whether or not that's actually what happened or not will depend on who did it and who is most beneficial to pin it on, but I'm sure there will be pictures that are illustrative.
They have combat divers (one of the special forces units is even the 1st Underwater demolitions Unit, apparently) and the average depth of the Baltic is 50m. So my guess would be: yes they have the capability in principle.