alt Hacker NewsI think Nordstream is more of a special case. It was clandestine, but definitely not terrorism. It was an attack on enemy infrastructure in pursuit of an actual, real-life shooting war. One can argue that it was a bad (or good) idea, or that it was/wasn't effetive, or even that its externalities were beneficial in the long term, etc...
But it's not really in the same category as casually cutting internet lines to your peacetime competitors out of pique or whatever.
Nordstream is also special because its destruction was not aligned with Russia interests. It limited Europe capacity to import Russian gaz lifting one of the reason which might have made the EU reluctent to fully support Ukraine (and causing a major economic crisis in Europe as a side effect).
Between this and the coyness of most European countries governments at the time to comment on investigation, it's not too far fetch to think that Ukraine might be involved.