Comment: The difference is that...

...in Exodus 32 it says distinctly that the people disobeyed a command. They were equating images of pagan gods with THE GOD that actually had led them out of Egypt, because of their despair and doubt over Moses taking so long coming down from the mountain.

I'm trying to understand: where is the command that we are to follow a specifically prescribed method or even timetable of fasting?

This bothers me in the same sense as when some Christians throw a major fit if someone disagrees with them on the precise method or mystical/literal substance involved with the Lord's Supper. All I read is the command to 'do this in remembrance of Me'. What difference does it make if someone believes somehow, mystically, it really IS transformed into the body and the blood, or just remains a symbol? But arrogance leads people like Luther to say 'I'd rather drink blood with the Catholics than mere wine with the Swiss.' Division over legalistic grey areas and ignoring the bottom line is discouraging.

But you are absolutely right: obedience AND intent are both important.