For what it's worth, Pokemon in Pokemon Amie and Pokemon Refresh do demonstrate some properties and whatnot, making the hand icon react differently. To give examples, touching Ferrothorn's barbs hurts, touching Rapidash's flames will burn the hand, touching the "cone" part of Vanilluxe freezes the hand with ice, and pure Ghost-types like Misdreavus seem intangible to the hand icon (Even at the red "pearls"/gems or whatever those are, around its neck.), given the appearance it takes and the sound "contact" makes, although the Ghost-type seems to still be able to react. Appreciating the effort, maybe?
Phantum and Trevenant share Dhelmise's Grass/Ghost typing, and seem "intangible" in the black parts of their body, but regular on the wooden parts of their body.
And in Pokemon Refresh, which seems to be Generation 7's equivalent to Pokemon Amie....
https://youtu.be/fFa99PCD1O0?t=43m12s
Well, Dhelmise seems quite tangible there. Then again, if it's voluntary intangibility, maybe it's simply letting the player character make contact with it to begin with because it's not worth the effort to prevent it or something? I dunno.
Being frank, I'm unsure how valid Pokemon Amie and Pokemon Refresh are, but I feel this might be helpful in debating this.
I apologize if it isn't valid; I'm new to posting here, although I've read plenty of pages. Hope this helps!