So I get the beef with the railway sabotaging. It's most likely to inconvenience workers and ordinary bods, and isn't really a target that has any value.
But a police fire arms training centre? Seems like sort of fair game to me. I've seen people mention that this might bring "heat" on their own left wing group which wouldn't engage in something so trivial, dangerous or illegal, and that certainly seems fair comment. Beyond that (and I wouldn't deny that that alone wouldn't be a perfectly good reason to want to distance yourself) what is the specific issue with this action?