Which is ironic when that non-racing boat is part of the race organization--considering that if it were a mark, it would not result in retiring...The preamble says one cannot violate IRPCAS and/or gov't regulations.....
... I would argue that a breach of the IRPCAS as referenced by the preamble to Part 2 is subject to exoneration under rule 44.1. However, because there was "serious damage" in this case, exoneration is not available under 44.1(b ) - "her penalty shall be to retire." Since she didn't retire, the PC gave her a DSQ. Different rule, same result.
Rule 44 doesn't say anything about exoneration for infractions of non-racing rules against non-racing boats, therefor one cannot exonerate an IRPCAS violation by doing a 720. Serious damage or no.
I would suggest that hitting a non-racing boat during a race means you're done, go home now.