You are absolutely right, and everyone should consider the dangers and your warning. BUT, before making a blanket condemnation of all wholesalers (I am not a wholesaler or connected with any of them) please consider the following points:
1. Yes, they obtain price quotes from the State and then resell their positions, basically. Can you do that yourself? Of course. BUT the pipeline is very long and very full, and you might not get a response to your price request for a year or two.
2. Some wholesalers have a pricing policy of $1,250 over redemption price for a tax certificate and $2,500 over redemption price for a tax deed. Depending on the property, that might be an acceptable amount of risk for a really cheap property. As real estate investors, we all have to balance risk vs. reward every day, all day long. This is nothing new. Even with a price tag $5,000 or $10,000 over redemption price, if you know that going in and think the likelihood of redemption is extremely low, that might be an acceptable risk. One must have enough knowledge to evaluate risk. Your post will hopefully help people with that warning to gain more knowledge.