According to that article it seems specifically related to corporations (C or S), but the parent comment advocated for LLCs.
The typical LLC has few or no investors (that are not managers or members), and it’s unusual for Delaware LLC law to provide much advantage over any other state in that case. YMMV.
Members are the LLC analog of stockholders in a corporation; if there were equity investors (passive or not) in an LLC then they would, by definition, be members.
“Few...investors that are not ... members” is impossible, as you note.