In the case of no filter however, we can expect that any intelligence would start expanding into the universe at near the speed of light.
Questionable premise. It isn't at all clear how close one can get to the speed of light, and even if this were occurring at 10% of the speed of light rather 99% the situation would look drastically different.
An Article on Motherboard reports about Alien Minds by Susan Schneider who claiThe Dominant Life Form In the Cosmos Is Probably Superintelligent Robots. The article is crosslinked to other posts about superintelligence and at the end discusses the question why these alien robots leave us along. The arguments puts forth on this don't convince me though.