"get-there-itis" isn't the sole domain of CSFlights, there are many pressures on a pilot when travelling, like not wanting to lose the hotel booking, car rental, family disappointment etc. etc. etc. Part of a pilots training, whether PPL/CPL/ATPL etc, is how to deal with this factor. ATSB are implying that doing a Community Service Flight (CSF) is somehow applying more pressure than a weekend getaway to the snow or a family wedding in Tasmania. To truly study the statistics you would need to look at all flights that come under this category - of course that data is not available. Maybe a better statistical analysis of Angel Flights would be to look at all incidents of VFR flights into IMC and then determine the purpose for each flight and find the percentage of those flights that are CSF's. Then you can say that whether or not there is something peculiar or not about CSF's.
On flying VFR into IMC in general, after doing my IR I read a few stories in the RA-Aus mag and spoke to a few people and the impression I got was that, because of whatever reason, a person found themselves entering IMC, they would generally tense up, be fearful to some degree and endeavour to get out of the clouds. Some persisted on, generally climbing, others would do a slow turn back all the while trying to watch their instruments. Obviously the ones who wrote the stories and could talk about it afterwards survived and the attitudes were mixed, everything from "it wasn't as bad as I thought it would be" to "I will never do that again!". Those attitudes probably determine the future outcomes for those pilots.
Learning a bit of Instrument Flying can be both good and bad, you need the confidence to only look at your instruments. Flying on a dark night is easier than day through broken clouds. At night you can only see your instruments, while during the day you can get distracted by glimpses of terrain and the tendency for visual pilots is to keep looking at the ground. All that head swivelling and turning will disorientate you very quickly. Certainly learn to fly and navigate on instruments but more importantly learn to trust those instruments.