There is nothing particularly wrong with this hypothesis. It makes a lot of sense qualitatively. To me at least, and certainly to the level necessary to 'believe that something might' be' blahing blah, blah, blah...
For N+1 phenomena in a chaotic system, N hypotheses can be promulgated which "make a lot of sense qualitatively". The problem is one of cherry picking which of those hypotheses are presented in accordance with the desired narrative, instead of simply enlightening more people about the actual nature of chaotic systems.
It may be in many cases, that there is resistance to the concept of a mathematically chaotic system, that it is terrifying and against worldviews which are controllable, said worldviews being desirable for those of certain inclinations.
I'm not pretending to know anything about the increasing sea ice in the antarctic, but if it is or becomes and observable trend I certainly would not be inclined to lump it in with the (fairly small set of) things which I throw up my hands and write off to 'behavior in a chaotic system'. A good start would be to explore the salinity data (if any.) That might be sufficient to reject the hypothesis right there. Or it might not.
If the 'climate science community' does make a good faith effort to generate and communicate a variety of other testable hypotheses and present this one only for public consumption, that's a bad thing. It would not be an unexpected thing to me, my feeling pretty suspicious about their 'science' at the moment.