I took the time to get the facts of the Lindsay Clancy case. If you search for "Linday Clancy case details" there is a lot of different sources, and it is interesting to say the least. It is astounding how the actual facts are always missing in the discussions, posts and videos, by most people.
In a nutshell, on one hand it is quite clear that had psychological/psychiatric issues. On the other, the extent of those issues are up to the debate. There is one point of contention which is extremely important, there are evidence that points to planning and premeditation (at least within the day of the event). Would not say that this definetely the case, but I would say it is likely to be the case. The "beyond a reasonable doubt" is the tricky part here.
If I was a juror, given this amount the information I have now, I would consider the possibility that she was mentally incapacited. It is a bit surprising that 11 people are completly sure of that, so either there are more facts pointing to that, or... well, both options are quite possible.
But the crazy point, for me, apart from the crazy people calling her a hero (which, even if you fully buy the legally insane defense, is completely absurd), that people are simply stuck in the guilty/not guilty part of the discussion. Either way you look at it, there are far more important questions to be asked.