It is a grey area.

Some report them being a government/private school/recruiter led trap to catch the troublemakers. China e-cities has featured a fair bit of discussion about this, saying that people who reported schools, found that the website reported said teacher to the school that they complained about, getting them into further trouble. Then again, a fair few people don't trust China e-cities either, that place is completely overrun with wumaos apparently.

Likewise with the reporting of the group by the China Daily Mail website. Neither side can be trusted.

Another issue, is that there is more or less no way that it could be a fully legal organisation. Non-government backed trade unions are illegal in China and I can't imagine the government backing these guys. If it does actually exist, prepare to be heavily monitored if you attend any of the meetings.

If you are suffering issues relating to a school and must seek the services of somebody who is not a lawyer, Beijing Blacklist are probably a far safer bet. At least they fully admit to being an illegal vigilante organisation.