Here is one source with an explanation of how 'do re me' came to be. I will quote in part and then give a link to the entire article, which is interesting.

" Guido D'Arezzo, a monk who lived in the early 11th century devised a version of the staff that is the precursor of today's staff. Some of his practices also contributed to "sight-singing"--the reading of music at sight. He also started the practice of using the Latin syllables of Do, Re, Mi, Fa, etc. to symbolize pitches. "

So you can blame it on Guido. Here's the website:
click here Music of the Middle Ages and Rennaissance