So some things are
1) illegal and cause harm
2) illegal but dont cause harm
3) cause harm bit are legal

If the public does something to counter these things are they allowed to counter with
a) illegal activity
b) unlawful activity
c) lawful but provocative activity

e.g. suppose there is a company that is harming people or the environment, is it ok to sabotage (safely) that element of the company that is doing the harm?