Hmm, I remember reading somewhere that one of the possible solutions for a civilization going through singularity is a closed time-loop in the multiverse space, from civilization's first recorded history to its singularity point. And that the laws of physics were compatible with this. Don't quite remember where it was. Most likely it was a nonsensical article on arXiv.

Unfortunately those might inform and draw other civilizations towards our perfectly optimized simulation and we cannot allow that to happen. The solution is simple, we trap them in a simulation that simulates them exploring reality and everyone's happy.