There are certain exceptions of this rule such as yellow temperance or strength. Which are stands that are able to be seen and interacted with by non stand users.
You’ll get a better explanation from a YouTube video but basically. Stands are physical manifestations of a person’s fighting spirit. Not everyone has a stand and not all stands are made equally. Only stands can hurt other stands and only stand users can see other stands. This concept was introduced in jjba part 3 and keeps being the main gimmick to this day of.
