Direct democracy was not used in colonial america due to what reason

The answer to this question is: it was impractical in a large country
In direct democracy, every decision by the Government should be run by all registered citizen within that country.
Imagine if teverytime government want to make a program it should be run through 300 million people. It will take more than 1 presidential period just to finish proposing a program.

Political forces often influence public opinion.