'Share the road' is a very common sign in Tasman and perhaps this is a mantra we should all adopt. There are legal 'rights and wrongs' and recommendations, see http://www.nzta.govt.nz/resources/roadcode/cyclist-code/about-cycling/cyclist-responsibilities/ , but these are just a framework for safe road use. Personally I always try to err on the side of caution whether riding or driving and this doesn't seem to slow me down significantly, and certainly by much less than an accident would!
However, no matter what road rules say, overtaking anything when you cannot see a clear road that offers enough space to complete the manouvre is dangerous, and I'm sorry Les, I don't understand why you would want to endanger yourself and others, which clearly you were doing when the photos were taken.
Could / should the cyclists have been bahaving differently? It depends, but from the photos it appears to me that overtaking a single cyclist in that situation would have been potentially dangerous, and if they had all have been strung out in single file then you would have needed much greater length of free road space to overtake, perhaps they shouldn't be allowed to be on the road at all?.
Yes it would be good if there were cycle lanes everywhere, but that just isn't viable in the short term.
One other thought, if every cyclist were in a car, what impact would that have on traffic congestion, parking and the environment?
When we're on the road we all take up space and, it could be said, get in each other's way, but roads are ours to use and enjoy, not mine of yours! Let's just share and be safe!