This is one of the most fundamental and serious flaws in Leftism, and they are so arrogant they never even see it.
They have zero humility or introspective capability, but a lot of arrogance. They think they are the smartest people in any room.
So, this is why they thought they could get away with this entire farce. They thought none of this would ever see the light of day. They did one of those jobs that would pass a cursory glance, because that was all they ever thought they would need.
They broke laws because their Leftist ideology tells them that the ends justifies the means, because their ends are, in their minds, more noble than anything and so, anything is worth ignoring, bypassing or destroying if it gets in the way.
And like all liars who scheme, the truth eventually is out, because they think they can see everything and take it into account.
They just didn't take into account Trump winning an election.
This was Watergate on steroids.