Grief is defined as the unauthorized editing of another players build. You wouldn’t, as a normal player, be permitted to make any changes to a build regardless of the situation without it being considered grief.
If you find an inappropriate build, you’d use /pos at the location of the build, then report it(and share the /pos feedback). It’d be up to staff to decide whether or not its worth removing and placing a ban on the builder.
Breaking it makes reporting it useless, as you would be making judgement in place of a staff member to begin with.