It may have something to do with his having been sexually assaulted a couple years ago.
In a video a couple weeks ago with Vanity Fair I think, he talks about a time he got off on the wrong train platform, and he asked a guy to help guide him to the right platform.
Instead, the guy took him by the hand, took him to somewhere hidden from public view, and placed it on his dick, and he then repeatedly, and forcibly, groped Tobey's junk.
So, he might be adverse to people objectifying him in graphic terms after an experience like that.