There's plenty of threads on how to fight these guys out there. Three tips off the top of my head:
- Build lots of starbases as bait - the Dread Lords, for some reason, zero in on them. It's a good way to lure them away from more important things.
- Avoid a straight up fight when at all possible. Target their transports and defenders, but run from everything else. Conquering their planets isn't that hard, and it's all you need to do to defeat them.
- The Eyes Of The Universe wonder is pretty much priceless when fighting Dread Lords.
The thing is, I bet that the random number generator that determines the events does not reset after every reload.
Try staring a brand new game to randomize the random number generator.
Unfortunately, that won't work here - the Dread Lords are automatically included with the Milky Way (and aren't mutually exclusive with the mega event either, as one particularly grim game proved). The only way to prevent them from showing up on the map is to mod them out.