With press-fit, it's not uncommon to use bearing retaining compound like Loc-tite 680 or similar. The problem is that a parting agent of some kind should also be used to avoid a permanent bond. I fear that is what has happened here.

The bearing retaining compound should be unnecessary if the press fit cups screw in to each other like they do here. But it would be totally understandable if someone mis understood and used it anyway. Permanent bond + immune to torque & shock loads.

I like the suggestion of using a tiny Dremel type tool and cutting the connector tube from the inside out so that the cups are susceptible to shock loads again. Then beating it with a Park Tool headset remover tool. You might even be able to get some leverage action by inserting a broom handle or similar after the cut.

Upon reassembly, grease the connector tube so that they don't bind or bond to each other. Don't bond the cups to the frame. The force from each pulling together against eachother should be sufficient.