The SEC does have rules pertaining to privately traded investment. They are normally more lax than for publicly traded companies, and therefor normally require the investors be accredited. The investor is expected to preform more due diligence. https://www.investopedia.com/terms/a/accreditedinvestor.asp

If you are confused about how SPACs work, and the OP article didn't help, the investopedia is good https://www.investopedia.com/terms/s/spac.asp

A SPAC is basically a vampire company that is publicly traded, but which has no operating business. Its sole purpose is to merge with another company, usually a private company, by expending its founding capital to buy the target. After the merger, the private company is now public - it trades on an exchange, has to file 10K’s, has to abide by Sarbanes-Oxley, etc.

It’s a mechanism to take a private company public without an IPO. That’s all.