Even in a decent PR multi-party system. Our green party for example is environment first, left wing economics second, public transit, pro-agriculture, anti-nuclear, somewhere down the list is internet privacy.

Or maybe I could vote for the labour party, which are centre left economics, pro-EU, pro-housing expansion, pro-healthcare investment, pro-environment, somewhere down the list is internet privacy

The idea that there's a party that (a) both has the same views on all issues as you do, (b) has sufficient votes to get seats and (c) orders issues in the same importance you do, for everyone, is clearly not valid. More parties = more choices, and this is often better, but ultimately we'd end up with de facto direct democracy to have a party with the exact views for every person.

Similarly, even for myself, I consider internet privacy important. Maybe I should vote the for the pirate party then? Except I consider the environment more important and our pirate party is so small that it hasn't even considered a position on non-privacy related issues, never mind have an adequate plan for how we're going to make a transition from a heavily fossil fuel based power supply. Even on that environmental issue, I think the green party's anti-nuclear stance has historically been a mistake, but if the others are just going to build more gas plants, I'll deal with it.