Seems like the Russian government has little value for the life of these pour souls and those in the military.
What I think is this.
If the ship sails on a mission, it has to be manned. There is no much choices.
But this ship itself is scrap metal designed in seventies.
Now, imagine horrors of battle of Atlantic, old generation ships, single hull (no double hull protection) at night, with wooden life boats, in winter north Atlantic, under attack of submarines wolf packs. How to defend against torpedoes? Only by luck.
This is similar situation.
In armed conflicts at sea, this modern drone technology has not been experienced till now.
As red leg said, it would present a challenge even to US Navy.
These drones, most probably are made of composite materials (plastic), and low surface profile, This means early warning systems such as radars are limited in effect. Navy radars are certainly more sensitive then civilian radars, but nevertheless. Radar range is limited by the height of its antenna. Low profile plastic target is low profile plastic target, and when below horizon is invisible.
Secondly, to build such drones, you basically need a basement size facility, and to launch it you need just a trailer and some convenient access to the water. You dont need port facility, or large industry, which makes it impossible to prevent by bombing infrastructure.
Defense against these systems in final approach, I imagine to be similar to what they were experiencing in early stages of ww2 Atlantic convoys, or ships without escort at that time, without sonars, and radars at the beginning. Now lets imagine low visibility and fog? A Nightmare.
I think the best warning system could be provided by a drone imagery and IR, circling around the floating assets. Maybe. But who has that?