I had the same gut response to that photo, but (at least in the case of the first) if you look closely there appears to be a single-leaf sprout further down one of the stems, which is not poison ivy's pattern.

In the latter two photos with the smaller sprouts I could see the argument, but the leaves look to have very straight edges relative to poison ivy (and I would assume someone like this would be aware of poison ivy growing in an area of his property, especially if he has a blog about growing a plant that looks a bit like poison ivy).