I think you're confusing "motto" with "mission statement" or similar.
Let's pull up ye ole Dictionary:
[quote]mot·to
ˈmädō/Submit
noun
a short sentence or phrase chosen as encapsulating the beliefs or ideals guiding an individual, family, or institution.[/quote]
That being said, I'm perfectly fine with the motto being restricted to 100 characters. It could actually stand to get shorter, to be honest.