‘They’ are wrong. It is unambiguously a fusion. If I was inclined to see the hand of God in anything, it would be that the fusion site is ‘too good’.
Yes. Or more accurately, common ancestry predicts that there be a transition between an ancestral karyotype and the derived karyotypes. A fusion in the human lineage would have been the most parsimonious, but not the only possibility. Then again, all of this was resolved extremely quickly after the initial karyotypes were produced. Order of events was basically: Human karyotype (several years) other ape karyotypes (basically immediately) probably a fusion (several years) better quality karyotypes for everything (same publication) probably a fusion of these specific chromosomes in the human lineage at approximately this location (~20 years) actual sequence data confirming the fusion.