In other words, the Lord was not pleased to bless Spurgeon with much detailed insight in millennial eschatology but was pleased to block any vigorous assertion by Spurgeon of the views which he did happen to hold.
If you look at the texts which Spurgeon preached from the Book of Revelations, you will discover that he ordinarily just looked for evangelistic applications. He ordinarily did not do what today's prophecy preachers do--which is to elucidate zillions of doctrinal details concerning the supposed future millennium.
He specifically loathed the prevailing practice of trying to "peep between the folded leaves of destiny." He called his own era's speculations concerning Europe's position in the Lord's timetable as "the veriest drivel, mere bones for dogs." He said that the people who thought they had any of the details worked out for the timing of the Lord's return were destined for the inglorious revelation that they didn't know what they were talking about.
This is not to say that Spurgeon never presented his own position. He did. The article demonstrates that. But the article does not bring out the fact that Spurgeon admitted that eschatology was his weak suit.
(Having read Spurgeon's devotional Bible, I don't recall that he said very much at all about his millennial position in that devotional Bible.)
Another thing which the article does not bring out is that Spurgeon really was weak in eschatology. He seriously irked conservative preachers by endorsing one of the most monstrous books ever written on the topic of eschatology.
I am referring here to James Stuart Russell's infamous book The Parousia. This is the most famous defense of full preterism. It really is an incredibly nasty book of exhaustively stupid interpretations.
Spurgeon did not agree with the full preterist position, but he said that the book was interesting and harmless. But it's actually nauseating and dangerous.