The forest preserve sent me a PDF of their brochure on canoeing. Here is the disclaimer.
Canoeists on Illinois rivers receive permission from landowners whenever utilizing private property. Many of the streams in Illinois are bounded by private land. Any stream that is not legally public and navigable is private and can only be used with permission from the landowners. Obtain permission from landowners before launching, take out, camping, picnicking, portaging, or parking vehicles on private land. Remember that your conduct will greatly influence the landowners attitude toward other canoeists.
So yeah, that old man is probably right. You probably need his permission to be legal.
Why they built a launch to the south of there i have no idea. Maybe they are hoping to buy that property at some point?
There is a canoe launch and a parking lot just to the NW of that guy's property.
They sent me PDFs of maps of a bunch of FPs around there. looks on paper to be really nice.
2019 Canoe Brochure.pdf