Well, in fairness, the discussion hadn't proceeded that far yet, so I don't think there's really a basis to judge at this point. And I'll have to go back and look at that part of this thread, but I recall it being mentioned as a factor, but not necessarily the sole reason for Michael's actions, which come at God's command. But the Bible is clear Satan still has access to Heaven and accuses us night and day, even though Jesus in the gospels says He saw him fall like lightning from Heaven. That may seem contradictory, but according to scripture both are completely true. And there will be a future war in Heaven with him finally losing access. We aren't given all the details for that, just that it will happen and he will come to the Earth with great rage, and his deceptions will reach their highest level ever to the point that people will try to war against Jesus.
Using NKJV here's what the Bible gives us on that event (Revelation 12:7-12):
"And there was war in heaven: Michael and his angels fought against the dragon; and the dragon fought and his angels, And prevailed not; neither was their place found any more in heaven. And the great dragon was cast out, that old serpent, called the Devil, and Satan, which deceiveth the whole world: he was cast out into the earth, and his angels were cast out with him. And I heard a loud voice saying in heaven, Now is come salvation, and strength, and the kingdom of our God, and the power of his Christ: for the accuser of our brethren is cast down, which accused them before our God day and night. And they overcame him by the blood of the Lamb, and by the word of their testimony; and they loved not their lives unto the death. Therefore rejoice, ye heavens, and ye that dwell in them. Woe to the inhabiters of the earth and of the sea! for the devil is come down unto you, having great wrath, because he knoweth that he hath but a short time."
So anything outside of that is us filling in the gaps unless it's found and cross-referenced elsewhere in scripture.