As a leftie I have a firm belief in the worth of all individuals (and their opinions) and I believe all citizens have an obligation to engage in participatory democracy. By having compulsory voting we are telling people that they (and their opinions) have intrinsic worth and that they are responsible for society.
If you respect an opinion of an individual, then how FORCING those strongly opposed to voting is respect of their opinion?
Normally countries that have non-compulsory voting have governments that are more authorities, more right-wing and have a more defined social class system. This comes about because percentage of electoral participation goes up with sociometric status.
You do realize that it is a total lie eh?
By the way, "lefties" are all about "people" (i.e. groups), which is an opposite of Individual. When you focused on FORCING your opinion of what each individual should do, it is anti-individual, and it sacrifices an Individual (rather than respects). And as such thing as a group or society r just a bunch of individuals, this approach eventually destroys the whole Group of Individuals , one by one.