At present, human scientists are attempting to communicate outside our species to primates and cetaceans, and in a limited way to a few other vertebrates. This is inordinately difficult, and yet it represents a gap of at most a few SQ points. The farthest we can reach in our "communication" with vegetation is when we plant, water, or fertilize it, but it is evident that messages transmitted across an SQ gap of 10 points or more cannot be very meaningful. What, then, could an SQ +50 Superbeing possibly have to say to us?
How about, "Hello"? My cat is sentient enough to say "Hello" in a primitive form that I can understand. Sure, an alien civilization much smarter than us wouldn't be able to discuss topics such as advanced quark interaction with us, but why couldn't they say, "Hello"?
I don't think that the problem with communicating with alien life is an intelligence issue. It is far more likely to be impossible, or be an issue of the wrong communication medium.