No. It is it not "different" seeing as that very pipeline was attacked and damaged, along with the other one. Nord Stream 1 and 2 were both attacked and damaged. They run parallel for much of their path except at certain parts.
https://en.wikipedia.org/wiki/2022_Nord_Stream_gas_leaks
>block it from opening.
Yes, and given the energy crisis now affecting Europe and Germany, inflation, and potential shortages of gas when winter comes and/or next year plus industrial needs for natural gas as input, it is exceedingly ridiculous that Russia would preempt these immanent crises and throw away their leverage for potential alliance with Europe in opposition to US right as the mounting pressures incentivize Europe to abandon sanctions and push for rapprochement.
You bring up war crimes and war decisions. First of all all wars involved war crimes, including the current one on the Ukrainian side. But put morality aside for a second, I'm addressing interests and realpolitik. That Russia saw it in there interest to attack is one thing. I dispute that they saw it in their interest to blow up their own pipeline and their primary point of leverage and economic strength towards an alliance with Europe in opposition to their primary enemy. No benefit of the doubt is required here to see this reality.