Besides their company would be at stake if those jobs they put would be illegal, that is why it should be fair that both needs to be legally accepted. It is also the reason why they asked for legal certificates and other government records which proves the persons interests.
I think a similar question has been asked previously and Trustlogics already made an answer. Trustlogics with the help of their partner validators will verify information "legally". Trustlogics do respect the law and they want to be compliant with the law as well. Trustlogics will have partnership with countries similar to existing ones thus, as a company, they should be registered to be able to operate. However, Trustlogics platform is online and may involve work outside your country and may not have yet form partnership with your country, thus it is not illegal in a sense that the work provided is outside your country. I'm not really a legal expert, but I do believe that Trustlogics will do comply with the law and do their job legally.
I dont think this would be the problem. Trustlogics has to take good care of its name so i believe before a certain job vacancy has to be posted, they will need to require the proof of authenticity of that job or the candidate itself has to find out if the job is legit before accepting it.