It wasn't so much a decision on my part, but rather a limitation/feature of Stencyl. Text variable strings are case sensitive, so in order to make commands not case sensitive I would have had to write an excessive number of variations to each possible input.
Viewing post in The Great North Pole Escape comments
Hi, umm, I know this is about a year old now, but I think Stencyl lets you turn text into all lowercase with [TEXT].toLowerCase(). So you can take player input and transform it to lowercase, and then check against all your commands also in lowercase.
Too late comment maker away!