Personally, I think the last thing that the free software movement needs at this point in time is two subtly diverging GIMPs vying for attention.
If Glimpse survives, I can see confusion as to what plugins work with which version (quite frankly, there is enough confusion as is).
I also don't believe that the name is that big of an issue. It seems to be a purely American thing. The rest of the world just doesn't care enough to get behind it.
But then I cannot fathom why people lose their shit about the difference between "coloured people" and "people of colour". Again, this seems to a peculiarly American issue.
The comparison has been made with other splits. Usually, successful splits have been over issues that the main contributors have passionately believed in.
The LibreOffice/OpenOffice split was won almost before it had begun and had overwhelming support from the community right from the start for fundamentally free-software principles.
I can understand the Glimpse dev's stance and more power to them if they feel *that* strongly about it.
I just don't think there is sufficient reason or justification for it to succeed.
I think a good comparison would be Devuan. I have to take my hat off to them for standing up for their principles and they support a need. But it is never going to take over from Ubuntu or Mint.