I certainly grant that voting for a small party has a nonzero effect, I just think it's not very large.
As a member of the left party, I would like to read some more detailed critique.
On minimum wage specifically, i see the big underlying problem that people's sense of dignity is tied to their income or how much society values their work. This is probably quite bad already, for example my dad has really poor rent and he commonly expresses great regret about having been so generous throughout his career (he was a lawyer and often defended poor people for free and such), instead of taking pride in his generosity. This is on track to get more and more of a problem as more work is automated.
Raising the minimum wage reinforces the stigma that your worth is tied to your income. In this case, I've even seen this made explicit, i.e., raising the minimum wage to strengthen people's dignity. It makes people more reliant on their job rather than less. This makes it easier for employers to exploit them. It also raises the bar for what kind of jobs can be offered, which shrinks the set of things that we consider valuable.
I'm for the opposite of all of those things. Just give people money and do whatever you can to release the stigma. Decouple worth from income, expand the notion of what counts as work, etc.
Also how about we don't tell consenting adults that they can't do [a thing without negative externalities]? This is the principle that's often used to justify why gay people should be allowed to marry; why doesn't it count for work?
In general, The Left (the party) seems to disregard what incentives are set by their proposals, but I think incentives are extremely important. Minimum wage is the most egregious example, another is just imposing a cap on rents. I support giving people money to pay for their rents and building more housing. I would probably support a bunch of other interventions. But a cap just distorts real prices. There is a reason why rents change in precisely the way they do; enforcing crude rules on top of that will hit/punish people differently with no guarantee for fairness.
Last example is the wealth tax. Afaik this has implementation issues, but let's assume it works perfectly. Now say you have two people A and B, who both own 2 million dollars in their 40s. In the next 20 years, person A burns through that by endulging in various unproductive luxuries, ending up with say 200k at 60. Person B invests it and ends up with 3 million at 60. A wealth tax will hit B disproportionately, which doesn't make any sense. We ought to tax consumption (especially consumption of luxury goods), not wealth.