Lets not go down the usual PPRuNe slippery slope again...please
Indeed. Obviously a sad event, which no one wants, and everyone would work to prevent. But, something slipped, and the Swiss cheese holes lined up in a bad way. I have no special knowledge of the event, but, like most pilots, can imagine all kinds of scenarios. One might be right, the others just speculation.
The benefit in discussion of this sad event cannot not be to look for fault, but rather to refresh our minds as to how we will each be more effective in the future, preventing even the risk of such a thing, let alone the event.
A Cardinal RG and Kitfox both in cruise flight (I presume) would certainly be a mismatch in many ways a mid air could happen, and the Kitfox coming out the lesser does not surprise me. I don't think the Kitfox is actually a "microlight", but it sure is not robust in terms of a collision with a much heavier and tougher Cardinal.
Of course, I have no idea where the respective pilots were looking, nor even if the other aircraft was viewable at all. Let's remind ourselves that there are position combinations in which two high wing aircraft simply cannot be seen from the other without a full clearing turn.
I'm not saying "shut up 'till the AAIB report comes out", because discussion in the mean time can be very worthwhile. Speculation can be good, if it promotes safety minded thinking and discussion, but not speaking poorly about a pilot, when the facts are not in.
I, for one, will not be speculating about pilot failings, as I would not want that done about me. But I encourage people to think about and discuss. how to minimize these risks as much as possible.
As a side note, and as a firefighter and aircraft recovery person of old, The gasoline powered chop saw will get rescuers into a plane, but you'll want at least those two fire extinguishers, if not more. The sparks from cutting steel tube structure that way will set gasoline and fabric ablaze very easily - been there, seen that! With good resources, I would have gone in differently.