The "style insensitivity" decision dissuades me much more strongly than some case sensitivity style enforcement in the language would.

It seems odd to me that Nim developers chose to go with that "style insensitivity" (which I would have predicted would be highly controversial and very discouraging for many, many developers) but indentation sensitivity (which is less controversial, but still more controversial than indentation insensitivity; shockingly large numbers of people dislike it, including me at least when combined with some other language features).

If the goal was widest possible appeal and adoption, those two decisions should have been swapped, I think. If the goal is related to some specific philosophical stance, however, I suppose every language developer who doesn't just want to recreate PHP or VisualBasic needs to pick the hill on which he or she is willing to die, and only time will tell whether it will be worth it.

The goal of any language designer is not to appeal to the widest possible group of people but to create a language that appeals to them. In this case style insensitivity is something that Araq wanted in his language and so he implemented it.

Compared to the horror of case insensitive identifiers?

A bit hyperbolic, there are loads of languages that are case insensitive.

Are you really only using case to distinguish different variables? That seems more error prone.