It's to promote more fighting.

The Defense station is a big space station, that helps your family to defend against bigger opponents. 30% of every attacking enemy fleet in a system, where the defense station is stationed gets destroyed. Only the family leader is able to buy and move defense stations. Defense stations can only be moved to systems where your family owns at least 70% of all inhabited planets. If you own less than 25% of the planets in a system where you have a defense station, the defense station gets destroyed upon the next successful attack of an enemy against one of your family members. Every family has a max of 10 defense stations.

Do you own 70% ?

lol ekszeed there's no button to move it, thats the bug.

grrr...

LG, this is being looked at, yes. I checked on our testing version and the bug doesn't seem to exist there, so it is something that Torqez and Stefan will have to have a look at. I can see where the bug is but I don't think I can fix it.