So many things about this are bizarre, that it's difficult to know where to start. What I find most perplexing, though, is that this comes out of the stable of "Bible-based" Christianity, that we know over here as evangelicalism. I'm always amazed by the ability that people have to devote themselves to the careful study of what the Bible says, and then to come out believing the exact opposite.
In this case, the words of Jesus are very clear and don't really need much interpretation: "no-one knows the day or the hour ... only the Father". "You do not know when that time will come" [Mark 13:32-33]. This thought is backed up at a number of other places in the New Testament. You'd have thought that would be enough for a "Bible-believing" Christian. But our author (strangely anonymous) is determined not to let the plain sense stand in his way. So we have pages and pages devoted to explaining to us why the Bible in fact says the opposite to what it appears to say, and that judgement day will take place on 21 May next year.
Always Hope will be following with interest over the coming 9 months or so and is quite prepared to be proved wrong. However on the basis of Mark 13, the likelihood is that we will still be here on May 22nd, at which point it will be fascinating to see what response we get from "We Can Know".
Please don't think I am drawing attention to this just to sneer, silly though it is. To me it's more of a warning as to how far things can go wrong, and surprisingly perhaps, it's the evangelical Christians who are most vulnerable to this. It's one thing to say "we take the Bible seriously". It's quite another to actually mean it. It's far easier to carry on believing what we want to believe, and make the Bible fit what we think, than the other way around. Most of us are more subtle about it than "We Can Know", but we still do it, at least sometimes. But if we really want a Christianity shaped by the Bible, we need to be brave enough to allow it to do the shaping.