Your wife shouldn’t have dug that hole, Jim.

I have been rewatching again.

This sentence lives rent-free in my brain even during the seasons. I always wonder why. I thought I knew it - and that she should not have dug and find the drawings of the monsters to solve her Anghkooey problem.

I think the reason is a different one.

During my rewatch I noticed Jim’s questions.
He is highly analytical due to his job and what he did was the best idea anybody in the whole town had. He wrote the questions into the wall.

Creatures: why do they eat/kill. Etc.
Talismans: How many, how do they work and can we recreate them etc.

And that was just a small section of the wall.

I think the reason why Tabitha shouldn’t have dug the hole, is simple. The digging caused the house to collapse for whatever reason. The BIW maybe? He did send Victor for her so he knew in advance that it would happen.

The MIY? Probably just mentioned the digging because Jim would have figured it out in no time, with the use of the wall.

He sounded as if stating a sad fact,
not that it was his doing.

Additionally I think that the BiW controls the plot/story of Tabitha and Jade, whereas the MIY has a different agenda that seems more personal.