) Joseph Cao took out a similarly entrenched Democratic Congressman in a heavily Democratic district.
I am aware of that Cao won by a tiny fraction of 1% and Jefferson had been in trouble for more than one term. My district is not nearly as Democrat or minority as Jessie Jackson's district, BBTAIM there was a strong coalition including many Democrats to rid ourselves of Jefferson. I walked two precincts for Cao.
2) It is common for Congressman to run unopposed for reelection in the House on both the Republican and Democratic side.
Which again was not the case here and is thus irrelevant.
) It's also common for flawed candidates to win reelection over and over again
Not common for the incumbent to not even campaign, be long gone for months and under investigation and win with over 70% 0f the vote, you see that as normal i see it as abnormal.