Why did Michael Flynn Lie?

In the wake of the Michael Flynn indictment and plea bargain several experts have wondered why Mr. Flynn lied to the FBI. His contacts with Russian and other officials were apparently not illegal. They were also over a month after the election, so had nothing to do with Russian interference with the election. So why wasn't he honest about his Russian contacts during the presidential transition?

It seems like the experts are ignoring the obvious. President Obama announced sanctions against the Russians for interfering in the election. There were frequent stories in the press claiming or speculating about collusion between the Trump campaign and the Russians. In this environment, an admission that Mr. Flynn had talked to the Russians during the transition in December would be transformed by the press into an admission that he had colluded with the Russians during the campaign. With the inctment a few days ago ABC wrongly reported just this and there is media speculation that Flynn will now tell all about campaign collusion.

Mr. Flynn likely also thought his phone calls were private. He wouldn't know the government was listening in on his conversations (though given today's technology, we should probably all assume our conversations are not private). So he may have thought they couldn't prove he had made the calls.

Given the constant calls for Russia investigations from the media and congress, is it any wonder Michael Flynn didn't want to give anti-Trump forces ammunition for their campaign against he new president?