I guess I'm talking about drone defense in more of a "Coast Guard" scenario than a "Navy" one. If there is some mass drone swarm coming at your cities you probably want to take a Navy approach and shoot them down by whatever means necessary.
In the case we're talking about though, the Russians are just able to fly their drones over European countries with impunity. Now these may not yet be armed, but you can't just let another country violate your sovereignty. If a drone is operating very close to a commercial aircraft, or there's a good chance of collateral damage, you may choose not to shoot it down, but you do need to demonstrate that you have some defense and that there's a good chance that they will be shot down.
In the case we're talking about though, the Russians are just able to fly their drones over European countries with impunity. Now these may not yet be armed, but you can't just let another country violate your sovereignty. If a drone is operating very close to a commercial aircraft, or there's a good chance of collateral damage, you may choose not to shoot it down, but you do need to demonstrate that you have some defense and that there's a good chance that they will be shot down.