This is an instance of the "broken window fallacy". To understand the nature of this fallacy, I highly recommend Economics in One Lesson by Henry Hazlitt [0]. It's short and easy to read.
However, Hazlitt's lesson is not the complete story. The question that Hazlitt does not answer is, what is "the long run", and how exactly do the gains from productivity get distributed to "everyone"? This is likely where a lot of leftists would object to Hazlitt, arguing that it's better to protect current jobs than to let capitalists (or whoever) suck up all the gains for themselves and never redistribute them. You can argue about the semantics of whether it's possible to "hoard" wealth, but ultimately there is some merit to that argument. But the fallacy remains the fallacy, even if wealth redistribution is an unsolved problem.
[0]: http://leeconomics.com/Literature/Henry%20Hazlitt%20Economic...
I struggle to understand this. Do people who hold this point of view wish we got rid of cars and instead manually carried materials everywhere? Should we ditch earthmoving equipment in favor of shovels? After all, that would employ more people for longer.