Why are liberal Democrats so against voter ID?

Because it's an unfunded mandate that won't be equitably enforced. Now if you fund it properly from conservative Republican coffers (since they're the ones asking for it) and have equitable enforcement of the policy under penalty of death ( as in if there is inequitable enforcement everyone in the implementation and enforcement arms are immediately executed and their latest votes stricken from the record), I might be willing to go for it. 

No illegal has ever voted (there are multiple studies and investigations proving this).

Voter fraud is extremely rare.

Almost every state already requires some form of ID to register to vote.

Making it harder for people to register to vote, making it harder for people to actually vote, and promoting voter suppression legislation to stop peoples votes from being counted are all Republican tactics.

"Why are liberal Democrats so against voter ID"

We're not, we're against BS regulations for non-white voters.

Why did Republicans vote to remove Section 5 of the Voting Rights Act of 1965 which which required certain states and local governments to obtain federal preclearance before implementing any changes to their voting laws or practices as to avoid voter suppression. 

Research shows that preclearance led to increases in minority congressional representation and increases in minority turnout.  Five years after the ruling, nearly 1,000 polling places had been closed in the U.S., with many of the closed polling places in predominantly African-American counties. Research shows that the changing of voter locations and reduction in voting locations can reduce voter turnout. There were also cuts to early voting, purges of voter rolls and imposition of strict voter ID laws.  A 2020 study found that the jurisdictions which had previously been covered by preclearance substantially increased the rate of voter registration purges after the Shelby decision.

There is no point in debating you when you have no idea what the actual issues are.  Instead you repeat conservative talking points. Get yourself an education.  Then we can talk.

Contrary to what Repubs preach, you have to be a registered voter to use a mail in ballot.

Their lame arguments against anything that makes sense is embarrassing.

Oh stop. We show ID its cons that dont. That are not registered voters and vote  3, 4 times.