Question

What was the belief of those who opposed the formation of political parties? what was the belief of those who supported them?

Answer 1

Many of the founding fathers believed (and turned out to be someone correct) that political parties would lead to the disintegration of the Union. People in favor of them thought they would foster progress.

Answer 2

The belief of those people who were against the formation of political parties was that the political parties were a threat to the government and they can divide our nation by discriminating against them.
On the other hand, there were people who were totally supporting the formation of political parties and their assumptions were that it is natural that people would disagree about issues. Also, they knew very well that people having similar views ought to confederate.