I see your point. However, if they were some kind of activists, we would have heard their manifesto by now. If they were simply trouble makers, I would have expected them to get bored (and maybe scared) a lot sooner. The list of reasonable candidates is a bit short. I wouldn't put it past the Russians (for example, I don't mean to point fingers) to cause trouble just for the sake of causing trouble. Also, even if this particular tactic becomes harder in the future, it shows just how pitiful the response has been. Whoever it was tested us, and we failed.

No company in their right mind would sell anything like that for less than $10k. Try £100+ as a starting price for one unit. It's aerospace and defense equipment and the airport is losing a truckload of money.

One of the article was giving a £16M figure for a 6 pack of the Israel Dome system.

The airports and pilots actually raised the problem with the UK government for years, to the point where in 2017 a law was passed that forbids to fly drones in the vicinity of airports and other sensitive areas. Aviation activism is similarly the reason for newer drones shipping with geolocking capabilities enabled by default. The problem is that the mainstream political scene saw these changes as resolutive (which they are not, as we’ve just seen) and just dropped the subject. This goes double for the UK, where Brexit has basically frozen any political and governmental activity that is not absolutely essential.