There’s a very straightforward and plausible rationale for Russia (specifically, Putin) to do it: coup-proofing by forced commitment to not turning the oil back on, like breaking your own steering wheel in a game of chicken and throwing it out the window. There are presumably elites in Russia who would like to see the war end and go back to business-as-usual so they can get their assets and incomes back, and blowing up the pipeline signals to them “that’s not happening. Total commitment is the only option, so don’t even bother trying to replace the current leadership.”

Is this definitely what happened? Of course not, we don’t know who did it. But it is a perfectly coherent and plausible claim, and so your hyperbolic statements about “what idiot really believes…” etc. only serve to demonstrate that you haven’t bothered learning about anyone’s position other than yours, and thus that you yourself probably shouldn’t be listened to.