“What I would find patronizing is someone thrusting a painting at me and saying “Say something mathematical!” I think it is equally patronizing to ask an artist to saying something artistic about the Singularity or a poet to say something poetic about math.”
It seems to me that the original invitation was for artists to participate in the discussion. To me this isn’t absurd at all. No one was asking them (as far as I can tell) to “say something artistic.” Rather, there was a recognition that those who self-identify as artists may have a different perspective, whether that perspective itself can be considered “artistic” in its own right or not.
It’s not unlike a group of male advertisers sitting around a table considering whether they should solicit a female colleague’s perspective on a particular ad campaign. That might be considered condescending, but its equally likely that her opinion may be of value, if not uniquely “feminine” in some way.
Nonetheless, as you suggest, a vague invitation to “participate” won’t necessarily generate anything useful.