[conanite]

I suspect the "great" Britain distinguishes it from the other Britain which is a nearby French province, ie "Grande Bretagne" vs "Bretagne". Ireland is still not British! The "British Isles" was a useful term for a dominant power while it lasted.

[pacaro]

No. It was simply the descriptor applied to the largest island in the archipelago. The cultural layer followed, sadly England in particular and the UK in general have done little or nothing to address colonial and imperial legacy

[mutatio]

No he's right, it has been used historically to distinguish it from Brittany. What on earth are you talking about regarding imperial legacy? It might be used in a sense to project national potency, but the naming never derived from any imperial motive. It seems to me along with your earlier comment, that you're fixated on self flagellation and a conclusion that just doesn't exist regarding the naming.

[pacaro]

From the same Wikipedia article

"Claudius Ptolemy referred to the larger island as great Britain (μεγάλη Βρεττανία megale Brettania) and to Ireland as little Britain (μικρὰ Βρεττανία mikra Brettania) in his work Almagest (147–148 AD)"

I feel that the reference to English and UK colonial and imperial legacy is more a recognition that the term has in the present day become controversial, and, to some, offensive for a number of reasons which include: a history of oppression and/dominance, both within the archipelago and beyond; a jingoistic element within the UK population that considers that to be a good thing; the conflation of the various meanings of _great_

Those things are distinct from where the name came from ≈2,000 years ago, but speak directly to why it might be offensive today