A learned friend of mine is of the opinion that it is forbidden to learn from a Rabbi (or anyone else) who is known to have sinned. He used the example of a particular Rabbi caught in a scandal so malodorous he was forced to leave his community and indeed the country. After a number of years overseas he has quietly returned and has begun giving a shiur to a small audience who are obviously able to overlook his past. My friend rails against what is happening and compares it to 'drinking from a sewage pipe'.
This attitude seems far too stringent to me. I have asked him for sources for his opinion, which he is preparing.
I expect the halacha is far more nuanced than what he says. I am looking for sources for and against learning from such a person. For example,
- forbidding learning from such a person
- the danger of learning from such a person
- judging someone to have done teshuvah
- learning from any available source