It is clear that once one accepts an academic job, it is just not right to continue interviewing for the same type of academic job.
However I (and most others on both sides, I would imagine) think it is perfectly reasonable to continue applying and interviewing for permanent faculty jobs after accepting, say, a postdoc offer. Call this situation A.
However it is much less clear to me how the situation can be viewed from the new employers' perspective if after accepting an academic job --- whether postdoc or faculty --- the future employee applies for a (dream) industry job that just opened up. Call this situation B.
I fail to see how situation A is fundamentally different from situation B, unless I miss something.