Is it permissible to visit a grave for the sake of admonition and lesson, even if that grave is the site of sacrifice and vows made to it?

Question:
May Allah reward you, Honorable Shaykh. This questioner says: If a man goes to visit graves where people call upon others besides Allah and sacrifice to them, he says, "I do not do any of the types of shirk (associating partners with Allah), but I attend to visit the grave of this wali (close friend of Allah); because the Prophet (peace and blessings be upon him) encouraged us to visit graves, and the awliya (close friends of Allah) are more deserving of this visit than others."

Answer:
If there is munkar (what is wrong) and shirk is the greatest of what is wrong, do not go to it. Do not go to it, because they will use you as an argument if they see you visiting. They will argue with you and say, "So-and-so visits the grave of such-and-such a wali, and people there sacrifice and make vows." This is an endorsement of them. Even if it were your father’s house, if there is munkar in it, do not visit it until the place is cleared of the munkar. If there is munkar in a place and you are unable to remove it, do not go to it. Yes.