Why are small business owners considered petit bourgeoisie?

This question is coming from another post where I was asking what the intelligensia and petit bourgeoisie difference is (https://lemmygrad.ml/post/10748355)

This is a comment I left when discussing: "This one is really difficult for me to grasp, it’s probably my ignorance and lack of knowledge, but why would someone who is a small business owner that doesn’t employ any other worker be bourgeois? Are freelancers and struggling artists who are trying to get their foot in the door of an industry also in that class? I hope I don’t come off as aggressive (I just read back what I wrote and it sounds a bit like that, but I swear it isn’t :D)"