Very broadly speaking, there are two kinds of writers: those who just start writing and go where the writing takes you, and those who develop an outline first. In the case of the first set, it is vital to do a heavy editing pass or re-write iteration.
I don't think anyone tackles a thesis without some kind of outline, but I also doubt the universality of this advice. Some people need to explore their ideas before structuring them.
All that being said, this is full of good advice, such as:
"When you write for them (the audience), you put forth effort to make your product good: neat, complete, proffed (sic), unified, cogent, etc. That is, you craft and polish a well designed product for them to read. However, if you [yourself] are the audience such effort is a waste."