Well obviously, because its sung from the perspective of the revolutionaries. "Look Down" is sung from the perspective of the prisoners. And "I Dreamed A Dream" is sung from Fantine's perspective. It doesn't mean that the play overall is necessarily endorsing that perspective.
Why is there no song sang from the perspective of the monarchists? why is the only law enforcer made to look bad? Why is society made to look bad under the monarchy rule?
The play is made to make the revolutionist look good
Well, theres an accurate version of that song https://youtu.be/nPDH4lZB6HU
The play is made to make the revolutionist look good