If you look at this article, you will find that this person argues principally, not from evidence, but from a presupposition (although she does use evidence, much, but not all of which is in fact true). What I mean is this, her “evidence” that Mark was written after AD 70 is that Mark discusses the destruction of Jerusalem in AD 70. In other words, this person is assuming, “obviously” that Mark (and Matthew and Luke) cannot have supernatural prophecy of Jesus. Therefore, if it talks about the destruction of Jerusalem, by the presupposition, it must be written after AD 70. No, this unbeliever argues, obviously the Bible cannot be inspired by God, because God does not exist. Therefore, Mark was written well after AD 70, and therefore the person we know of as Mark did not write it.
Such presuppositional arguments, also called circular reasoning, are only as good as the presupposition. But the presupposition is flat wrong. God is real. Jesus is the Son of God. Jesus was raised from the dead. Jesus is more than capable of predicting the destruction of Jerusalem in AD 70. Besides, if we accept the argument of this person, then whoever wrote Mark is flat-out a liar and a deceiver, because this false witness is putting words in Jesus’ mouth that he never spoke. The same would be true of Matthew and Luke. The authors of these two “anonymous” gospels also would be giving false witness about Jesus, and the church, many of whom actually knew Jesus, would have to have been duped into believing this deception. This argument is circular and it is based on a presupposition that is flat out wrong. This leads her to make bad and even illogical arguments, for example, proposing that the author of this book from around AD 70 (which is way too late for Mark, based on the evidence) was a liar and a deceiver. You can safely dismiss this article as bad based on both uncareful use of the actual evidence, and on the use of faulty circular reasoning using a presupposition which, itself, is in fact false.