The issue is poor security in electronic voting machines produced by the major US manufacturers. I don't think many Slashdotters are inherently opposed to voting machines. The problem is many of the voting machines used in US elections are poorly designed and don't take even basic security precautions.
Let's take Diebold for example. They ended up having to rename their voting machine subsidiary to Premier Election Solutions because it was tarnishing the name of their company and was making their ATM business look bad. A computer science researcher did a source code analysis of their product in 2004 and remarked "this voting system is far below even the most minimal security standards applicable in other contexts." Another analysis concluded “the system, as implemented in policy, procedure, and technology, is at high risk of compromise."
It's a relatively simple process in some of these machines to reprogram them and change the outcome of an election. With that in mind, we need standards in place to ensure that people are not committing election fraud with e-voting machines. Until I can see independent studies on voting machine platforms that validate adequate security protocols, I'm going to remain skeptical about them.
For more information on security risks in e-voting machines, check out the Premier Election Solutions Wikipedia entry. It's pretty eye opening.