What it says on the tin. For some reason, the smart remote is marking Krastorio2 Tesla Coils (fixed structures that can charge nearby equipment grids using your base's electric grid).

Since I usually have the built next to train stations, to charge the grids of the trains (K2 also gives trains equipment grids and exoskeleton-like equipment that boosts their acceleration), if I drag over a part of the base while marking other nests for attack, half my trains get targeted strikes dropped on their heads...

Disable "attack enemy structures of any hostile faction" in per-map settings of the mod and see if it helps.

It does not, no. The Tesla Coils are still marked for shots. Might be something weird with whatever they have to do to work to charge grids and target nearby entities - maybe they're "enemy turrets" to some degree? I haven't checked their code to know for sure. They already have odd collision boxes, especially with other Tesla Coils.

The only way they can be targeted by smart remote is that they are marked as military structures in their prototype AND their force is specified as "enemy" or other force that is considered hostile by force you belong to (usually "player" unless playing pvp)

Scripts spawn a hidden turret under the coil when a tesla coil is placed, and that is set to the force "kr-internal-turrets". I've been trying to find where in K2 anything is specified about that force and am not finding it - do new forces default to hostile? This turret does target the player and entities the player owns (such as trains or spidertrons) when they have a specific equipment grid item in their grid, so I imagine it is considered hostile somewhere. The remote might be placing the target on the hidden turret, rather than on the tesla coil itself.