The spoofing is probably so drones think it's a no-fly zone (since the GPS signals say, "you are now at one of the Moscow airports"), so there's less surveillance by amateurs. Are weaponized drone attacks a credible threat?
[1]: https://www.theverge.com/2018/8/17/17703570/caracas-drone-at... [2]: https://www.reuters.com/article/us-saudi-oil-usa-iran/saudi-...