Oh sorry, can definitely see how it came across like that in retrospect. In terms of docker being easier or better than VM's, I think this is the best explanation (although it is maybe outdated even though it's only 1 year old) of how people often misunderstand what docker or vagrant are: http://stackoverflow.com/a/21314566/4696622
I've used both and I generally stick with vagrant because unless you are already on a linux machine, you will need to use a VM anyways at which point the whole 'startup time' argument is pretty much equivalent and an actual VM is a lot more useful for anything dev/toy stuff than a mishap of docker containers (well from MY experience of course).
I think both are cool and I'm sure someone much smarter than me can explain when to use one over the other but there really are a lot of people who discuss the pro's or con's but have little in-depth experience with either (not saying that about this, more aimed at HN comments I've seen). I also think knowing how to configure virtualenv's/conda is important because that is becoming a really fundamental part of python understanding (venv, virtualenv, whatever else options there currently are).
