Because if the trend persists, the entire ice sheet could be destabilized, as is indicated by some global warming scenarios for the next century and into the 22nd century.
I read the link, but I don't see a definition of destabilization. The closest thing was rising sea levels would unanchor the ice sheets and cause them to break up. That is far flung as you know, sea levels would need to rise orders of magnitude more than current trends and predictions for that to happen. Another candidate is the breakup and darkening of the ice surface from melting. But that clearly isn't happening except on the fringes. Most of it is whitening, just the opposite. "Destabilization" seems to be qualitative and speculative.