I noticed “scores of semi-automatic rifles” mentioned in the source article. Is this more a reference to “occupational shooters” or people who own deactivated firearms of this category?
It could be either, or neither.
You have to ‘give a reason’ for owning a semi-automatic, but the police are generally reasonable about that (something the gun control people don’t like) and approve most people without a criminal record on any credible grounds. But I think they might be less so if people want lots of such weapons (I only have one, so I have never dealt with such scrutiny), so it wouldn’t surprise me if these are professional shooters, who do have the easiest time with the laws.