Not true. At colleges where career survey information by major is shown, different liberal arts majors can be very different in post-graduation outcomes. For example, compare applied math versus molecular and cell biology at https://career.berkeley.edu/Survey/2017Majors . Or compare economics versus political science there.
This is not always the case either, but even when it is the case, it is still better to have results by major (like in the survey linked above).