There won’t be lines where the white voters are a majority
This is the biggest reason that compulsory voting like we have in Australia is so good.
It’s not a violation of free speech at all. You can always choose to just hand in a blank or deliberately-spoilt ballot.
But what it does mean is that the Government is forced to provide adequate resources to polling places to ensure that everyone is able to conveniently vote. You can’t get away with nearly as much voter suppression when everyone has to vote.