I remember the version where you could destroy structures with homing mines. That was a little silly and I understand the change.
The Orkulus is a special case since it is a moving structure. That's why I think it might be an oversight. Perhaps they forgot about this one moving structure when they made all the other structures not trigger homing mines.
I think the Orkulus should detonate mines if it moves into them.
The Orkulus is already the bait for Torpedo Cruisers - a fleet of 5 can easily take down an Orkulus, 10 for an upgraded one.
You dont need to tip the scales in a races favour, the Orkulus is already balanced in that it moves, because it fills the Offence spot in the 3 balancing issues of the game: Support, Offence and Defence.