What other candidates do you mean? Sanders has never made paid speeches to Wall Street groups. The Republican candidates (except, surprisingly, Donald Trump) have never claimed to support tougher financial regulation, an end to carried interest, etc. Do you think Cruz or Rubio or Christie told Wall Street bankers privately "I'ma gonna kick your ass!" But the concern about Clinton results from the fact that she has promised to crack down on banking abuses at the same time her and Bill's vast personal wealth are derived in large part from an industry that she would be called on to regulate. That is reason enough to speculate about whether there might be a discrepancy between her public and private remarks. And when someone acts like he/she/they have something to hide, they often do. Clinton could choose to take the high road, release her (probably harmless) transcripts, and challenge all the other candidates to do the same. She'd come out way ahead. But that's not what she's doing, and it says something about her character and attitudes -- like the private email server in her basement -- entirely apart from anything she might have said.
