Here's how I understand it, but someone more informed is welcome to correct me on this.
Blackhawk did R&D and designed the Gladius. They then hired a factory to manufacture the light. After a while the factory was allowed to manufacture more lights using the Gladius design which they then sold to another company, Inisght. (all with the permission of Blachhawk who likely got a good sum of money for it)
So it is pretty much the same light, made in the same place, just sold by a different retailer who didn't have to pay the initial R&D money. So they can sell it to you for less.
Blackhawk still gets good sales on their light by word of mouth, etc and most consumers are too dumb/ lazy to research and find the Insight Typhoon cheaper.
Hope this is correct and makes sense.