BMY – when someone gives advice to another person, he has to think very carefully about who the person is and whether or not this is good or bad advice for the person in question.
Obviously, that is one of the dangers inherent in giving advice online, and therefore one should always try to err on the side of caution.
The advice that you are giving Rebshidduch is advice that can theoretically either be okay advice or dangerous advice depending on the person in question.
If Reb shidduch were the type of person who has a very strong personality and hashkafa and is totally not attracted to this guy and there is no possibility that she would ever be influenced by him, then perhaps your advice would be okay advice.
However, it is clear from her posts that this is not the case at all. She has already been influenced by him (she turned on goyish music because of him) and she has a lot of contact with him (she is giving him rides). For her, this advice is EXTREMELY DANGEROUS!
“Chayecha kodmim”. She has to think about herself first. You are never supposed to do kiruv at your own expense.