I don't buy the bad apple argument from HomeVestors. If you know, or should know, there are bad apples, but don't do anything about it, you are a bad apple too.
Wholesaling in general has a dubious reputation. Some are good, but it's so easy for bad actors to participate.
When someone sells a property for 2/3 of it's value, that's a cautionary flag, even in the best of situations. Sometimes the seller is aware and has higher motivations to leave that kind of cash on the table, and that is OK.
Unfortunately, sometimes the seller is unaware and is being taken advantage of. It happens in every business, not just real estate. In real estate and in the case of the ProPublica HomeVestors investigation, people were screwed out of their homes and largest asset. That is not OK.
One of the tactics used was putting a cloud on title, even though the property had not been transferred yet. This made it nearly impossible or very complicated for adult children or other care takers to unwind an unscrupulous transaction that took advantage of seniors with cognitive declines. That is dirty, and happened often enough that corporate told franchisees to stop that practice.
There are plenty of ways to make good, honest money in real estate.