There are a number of sites that blacklist schools, though many of these are subject to pressures from advertising. There are so many complaints about posts being deleted from sites like Dave's EslCafe.com that complain about schools, where the interests of the owners lie 100% with advertisers and without any attempt to guarantee basic standards of decency over the employment conditions. In other places, a similar approach is taken, so that posts have been pulled after they paid for advertising. Where sites don't make this explicit, than I think there are grounds for complaint as they are presenting adverts without any quality control, though if they state that there's no control, then the user is free to judge their value.
There are a number of sites like the TeflBlacklist that have been operating for years and have not been closed down, which suggests that the generous protection the law affords to the owners of businesses still does not cover some of the horrors of ESL/EFL schools. While some accounts may be exaggerated, biased or false, and those that are can be corrected or deleted, the blacklists do the profession a favour by exposing some of the crooks and cowboys who are out there, and ESL/EFL is a profession where there are a frightening number of places that are shoddy or just plain crooked.