*sigh* Go on, then, cite your examples, because the Shivans in FS1 made no sense.
In
Pandora's Box, they set up an ambush to kill the player (but fail). Nonetheless...
In
Hammer and the Anvil, they are led to believe that they have already destroyed all the shield prototypes, and believe that the convoy which is actually carrying the shield convoy is just another convoy headed for Earth. However, once they learn the contents of the Cargoes, they actively seek to destroy them.
In
First Strike, the Shivans try to destroy the Taranis once they realise the possibility of the Terrans capturing it.
In
Shell Game, the Shivans drop cargo containers as a trap, knowing the GTA will try to capture them. The cargo containers then self-destructed, killing a few Terrans in the process.
In the Battle of Deneb, they sent the Eva to lead a secondary fleet while the Lucifer circumvented the blockade at Deneb. (Next though, in
Evangelist, they do something really stupid, just leaving the Eva out there to get exploded, I'll admit that was pretty idiotic on the Shivans' part).
In
A Failure to Communicate, the Shivans attack the Beta Aquilae Communications Terminal. Whether this is just the Shivans attacking anything that is not Shivan, or if they were actually trying to disrupt communications is up to debate.
In
Running the Gauntlet, the Shivans actually send in their flagship, the Lucifer, to a relative backwater away from the front, Altair IV, to neutralize the Rosetta and the convoy. The Lucifer was actively seeking to destroy any evidence of the Ancient data recorder to prevent the Terrans from learning their secret. This is IMO the best evidence for Shivans actually thinking in FS1.
They had an invincible ship. They could've been over Sol in a day or two.
No, actually. They couldn't because
they didn't know where Sol was.