I see a lot of complaining about the strategy of other players. If you've never played any browser game like this one (originally ogame), travian etc., the main target is to conquer. Of course this is also a great opportunity to meet new people, make some friendships, but still this is a game and competition. On the other hand you and as I seen also other players (link Hive account@potplucker ) blur the lines between the game and real life...
https://chainbb.com/steemnova/@potplucker/game-steemnova-thoughts-players-of-no-honor#comments-page-1

You have to attack other players if you want to develop faster and all moves are allowed, of course within the server law. And the law says you can't attack one planet more than 6 times per 24h (the exception is a war), and you can't attack new players which is blocked in the game itself. These are the main limitations.

There is nothing wrong in attacking weaker players, I would even say it is more reasonable because there is potentially bigger profit with the less risk. The player still have some option to defend. There is always at least one - to not allow others gain profit from our planets. Remember that one of the features in game are alliances. You can gather 5 weaker players and together destroy one whale so nobody can feel safe.

And complaining about colonization in other solar systems is nonsense. Do you want to play only in one system? Please read some strategies, manuals or maybe some FAQ made for ogame. Maybe this will help to clarify some doubts.