Or, those who lied did what we all do - rely on human methods to achieve what God could have done by being the Master of circumstances. Haman (Book of Esther) is about to commit genocide. A lie might have saved the Jews, but God just caused insomnia in a king. But I don't want to play the hero. I sometimes "rearrange" the truth for instance if my wife's feelings are going to get bashed. But I would never claim a lie to be good. Expedient maybe ... Good ... well ....
In Esther's case, it was God's will for her to tell the truth that she was a Jew. We are to be always in close communication with God, as to what to do and not to do in life. In addition to of course, abiding by God's Word and what it says, to the best of our understanding.
I can think of a reason why it's plain that Esther needed to admit that she was a Jew, in this case. It was because she needed to add additional incentive to the king's being willing to save the Jews - since He might not be willing to have his own wife, Esther - killed.
I know of numerous times in the Bible of cases in which God's people lied for good causes, and the Bible expresses no objection to it in any of the cases I can find in the Bible in which they did that. In addition, I see some evidences that Jesus at times - made statements that we would call "lies" - based on the fact that their hearers didn't understand what He meant, and based on the fact that His statements sounded like they meant something different (according to common popular understanding of what such statements ordinarily would mean) than what He really meant.) For example, when He told officials that if they destroyed the temple - He could build it up again in 3 days.
John 2:19-21
19 Jesus answered and said unto them, Destroy this temple, and in three days I will raise it up.
20 Then said the Jews, Forty and six years was this temple in building, and wilt thou rear it up in three days?
21 But he spake of the temple of his body.
KJV
Also, think of how Jesus told His disciples to "avoid the leaven of the Pharisees." His disciples thought He meant "bread" - but He meant, the evilness of their hearts.
Matt 16:6-7
6 Then Jesus said unto them, Take heed and beware of the leaven of the Pharisees and of the Sadducees.
7 And they reasoned among themselves, saying, It is because we have taken no bread.
KJV
Also think of how Lazarus' family and others plainly thought Jesus meant that Lazarus was only sleeping, when He said Lazarus was sleeping.
John 11:11-14
11 These things said he: and after that he saith unto them, Our friend Lazarus sleepeth; but I go, that I may awake him out of sleep.
12 Then said his disciples, Lord, if he sleep, he shall do well.
13 Howbeit Jesus spake of his death: but they thought that he had spoken of taking of rest in sleep.
14 Then said Jesus unto them plainly, Lazarus is dead.
KJV
And think of how the hired mourners plainly thought Jesus meant that He thought the dead girl was just sleeping, and laughed because of His having said so:
Matt 9:24
24 He said unto them, Give place: for the maid is not dead, but sleepeth. And they laughed him to scorn.
KJV