I love the iHunter app, it helps me easily identify public land. However, that's all we can do in Ontario as we dont have landowner information accessible to us. I can see that becoming very annoying an frustrating as a landowner... but if landowner information is readily available to sources like apps, this seems like an issue to be taken up with the province.
I don't think any landowner wants to keep their contact information a secret. It is the way people use the information now-a-days that is changing how landowners view allowing hunting on their land. I've had it many times where someone contacts me and asks for permission, which is granted, but I never see hide nor hair of them. Meanwhile, I have hunters at the gate that I turn away because of the area access already being given to another party, who never shows up. If I let two parties on, you can bet they will both start blazing away at any herd of elk or big trophy out in the open, often resulting in them wanting me to decide who's kill it is, charge the other guy with some sort of wildlife offence, etc. Just a full on hassle that never ends unless you manage access well.