The idea that the tactics were correct is so clearly not true that I don't believe that Wilder actually thinks they were. I believe there are other reasons behind his selection and his comments. Here is my best guess:
Selection
This was a game we should win comfortably, ahead of some big games coming up. It's a good opportunity to try/test a few things. Such as:
Clarke, Choudhary and BBD all have had very little game time. This is a good chance to get them some match fitness.
Souza is also coming back from injury. Giving him 90mins is useful as we need him back on top form for the next few games (and rest of the season).
Cannon is raw and we need to work out how to use him. It's useful to get him into some proper match situations and learn a bit more about him.
Hence, there are 5 players there that we essentially need to get up to speed, and so Portsmouth at home seems like an ideal match to chuck them in and get them in better shape for the big games, even if they don't quite fit together.
I also think the Souza/Choudhary combo is one that makes sense to test. It could be useful in some scenarios if we need to close out a tough game. It didn't work yesterday, but if we can get it to work then it would be useful.
Hence, that is my logic for the selection. Get some game time for key players and hope there is enough quality to get us over the line. Thankfully, there just about was.
Post-match comments
Now, no one on here is saying "the players played well, it was just down to the tactics". There seems to be universal agreement that most of the players were poor, apart from the subs.
Also, I think we can generally agree that Wilder is a great man-manager. And part of the way you do this is by saying things about your team publicly. Wilder wants a reaction from the individuals, and he's said what he's said to give them a bit of a kick, to ensure some of those individual performances don't happen again.
If Wilder comes out and says "don't blame the players, blame me", then the players can feel that they didn't do much wrong. Wilder doesn't want them to feel that.
So, my overly-optimistic self believes there is some method in this madness, and that we will see something very different on Wednesday as a result. Fingers crossed.