It's rhetorical.
Why did Joe Biden lie?
Because that’s what a serial liar does. Besides, a crook is not going to admit doing anything wrong, even if he’s just a small time crook or the biggest ever.
Comer knows the obvious answer to his question, but, he’s afraid to pull the trigger on the impeachment inquiry. He just wants to float the idea about Biden being a liar and not trustworthy. That’s the most that Comer and the GOP committees will ever do against the Bidens. Biden will run again for president, unencumbered.
Biden lies because he is of the class of people who lie as a normal course of life. They lie even when telling the truth would be better. They lie. They steal. They betray. It’s what they are.
It is easy enough to understand why Joe Biden lied about his business connections with Hunter Biden and the various foreign governments and oligarchs involved. What is more difficult is why he thought it could be concealed forever.
Joe Biden’s own big mouth and tendency to brag tipped his hand, as regards the leverage he used to remove the Ukrainian prosecutor investigating the corruptions surrounding the Burisma holdings.
Joe ain’t too smart. But greedy, yeah.
Com’on Man!
Shirley, you jest. Joe Biden lie? No. Joe Biden would never lie. He is probably the mostest honest president since George Washington.
He just forgot.
Sorta kinda sarcasm

Those who still ask WHY are feigning ignorance.
Why does the sun shine? Why does the earth revolve? Why do democrats lie? so many unanswered questions
Because he’s a lowlife, democrat prick.
Trump never used that video in his campaign. Puzzling.
In the seventies, politicians just outright lied to the American People. (”I am not a crook...”)
Well, Clinton saw how that worked and he introduced the “weasel word” defense to lie to the American People. (”It depends on your definition of ‘is.’”)
The calls to Biden from his son’s meeting were not to discuss the business. That stuff would have been handled between a third party (Biden’s brother, one of the kids, etc.). The calls to Biden were to show that Hunter could pick up the phone and his dad would answer. There probably wasn’t any “business” discussed—because that wasn’t the purpose of the call.
It’s another form of the weasel word defense. And people who “don’t want to know” will look at the literal evidence and say, “Nope, Joe wasn’t getting bribed.” And those people are the entire Democrat party and 99% of the media (I know—thats redundant.)
Until someone can prove without a doubt that money crossed Joe’s palm...this stuff won’t stick. Its as if the media and political base look at Joe as something “we just have to work through, until the next thing comes along.”
IMPEACH HIM ALREADY!
Why? Because he knows that he belongs in prison, not in the White House.