The pipelines were useless to the russian goverment beforehand since they weren't sending any gas through it. It doesn't matter what the protesters wanted, Russia wasn't sending any gas. So there was never an "alternative".
But blowing them up means that people get worried again. The worries about having enough gas to last the winter increases. Russia wants a fearful Europe, not a determined one. This plays right into their hands, and it doesn't really matter whether people know it was them.
They are waging a proxy war with NATO through the Ukraine. And the fact that they are also threatening nuclear weapons just confirms their strategy in regards to Europe. They want a Europe that is afraid of Russia.
But blowing them up means that people get worried again. The worries about having enough gas to last the winter increases. Russia wants a fearful Europe, not a determined one. This plays right into their hands, and it doesn't really matter whether people know it was them. They are waging a proxy war with NATO through the Ukraine. And the fact that they are also threatening nuclear weapons just confirms their strategy in regards to Europe. They want a Europe that is afraid of Russia.