There are long-established objections to nuclear from supposed green groups, making that understandable.

There are no similarly held opposition to trains/mass transit. Indeed, as the parent indicates, trains appear to have unanimous support from green factions.

Indeed, and our ecologists promote train a lot. But given the timing, I can imagine the rationale of this being an attack on the olympics and not on train, simply because train is attackable and plane not.

Maybe, though it seems as easy to attack the road network to me; which would move towards green ideals more.

I don't think climate protestors have some deep seated opposition to art but that didn't stop them from throwing paint at major artworks.