That is bizarre. I just added great Ciurses and removed it without hitch.
If you are using a MicroSD memory pull it out.
Do Settings/System.System update && system restart
Maybe then you'll be able to remove it.
There really should be an ADMIn way to do this but alas.
You should log out of the session with the Channel.
A factory reset might be in order.
PS. you can also go to Streaming Channels in Home find your Channel
it and try removing it from there.
---A problem clearly stated is a problem half solved---.