In the absence of good public opinion polling, we cannot know for sure why many people in the 1790s were attracted to the ideas of Jeffersonian Republicanism. Therefore, we are left to speculate. I would argue that there are two main reasons for the attractiveness of these ideas.
First, Jeffersonian ideas were very much the opposite of the ideas that the British government had been based on. The Jeffersonians believed strongly in an egalitarian society. By contrast, the British system had been much more hierarchical. It makes sense that people who had recently won their independence from the British system would be attracted to ideas that were very different from that system.
Second, Jeffersonian ideas were a good fit for the American society of the time. In much of the new United States, the vast majority of people were small farmers. This meant that they were relatively independent and they were relatively equal to one another. People living in such a society would be attracted to the idea that all people should be equal and that society should be made up of independent small farmers.
For these reasons, I would argue, Jeffersonian Republicanism was popular during this time.