legitimacy of authority

The whole issue of legitimacy of authority got mixed up. In the Christian world they have ordination as an attempt to decipher. But in the Jewish world the stringent indication of counterfeit authority is ordination. This is because true ordination stopped during the Talmud period. And that kind of ordination is the only kind the Torah recognizes as valid. So what you have today is anyone claiming ordination is by definition a fraud.
To some degree this was recognized in authentic yeshivas where true Torah was learned like the Mir in NY. But even there a kind of blind eye was turned to people that went to get the false kind of ordination you have nowadays. 
There is a such a thing as a true Torah scholar but that is more or less an unofficial position. That is a person that is recognized as knowing the Torah well and usually there is no doubt to who this applies.
The best thing is to refuse to ask questions or go to these false prophets of the Baal and to do with them like Elisha the true prophet of God did with the false prophets. 

The problem with authority in the Jewish world goes back a long way. The simple way to avoid the problem is simply to take note that religious clothing usually means someone is trying to get money out of real Jews, by pretending to know and teach Torah. The best approach with these people is to shoot them on sight  so as not to let them into your communities where they do infinite damage to your children.
The most explicit explanation of this problem come from Reb Nachman who thought most people play the role of teachers of Torah are actually demons. That is messengers sent on earth from Satan to trick people and give them a false counterfeit teachings.
This really began in the days of the prophets but is also mentioned in the Talmud and Rishonim. In short there have always been scammers from the Sitra Achra [realm of evil].