Perhaps we are talking about different things. There are no "laws against capital investment by anyone", if you want to invest go down to pretty much any bank or financial institution and open an investment account. Go out and buy shares or bonds and have fun. Back in the dot.com days people did this all day long and got the notion of a 'day trader' was born.

The laws that are in place are around liability and more importantly personal liability in the event that the investment goes south. If you are soliciting investment from accredited investors you can put in place some limits on your liability with respect to that investment, I do not believe that is the case if they are not accredited.