Think of it like a tool for packaging and deploying applications with everything they need. Its purpose is closer to package managers than being a secure sandbox for running untrusted users' VMs.
I'd be inclined to agree. The reductionist sum of mechanisms that make a Linux container have always been about detaching, multiplexing and partitioning kernel resource subsystems. Docker was the first program that really hyped it into the idea of being about application deployment, but I fear this gives people wrong impressions and makes the mistake of treating an emergent property as if it were a fundamental.
I have no idea what point you're trying to convey with the second part. That applications are not business logic over kernel resources is a curious argument to make.
that was my initial impression i got from reading some posts on the Docker Site, and perhaps there is no consistent definition of "package manager"--to me though, the most difficult tasks a p/m must do are: reproducible builds, dependency management, conflict resolution among transitive dependencies, and the like. But Docker does none of these things as i understand it.
I'd be inclined to agree. The reductionist sum of mechanisms that make a Linux container have always been about detaching, multiplexing and partitioning kernel resource subsystems. Docker was the first program that really hyped it into the idea of being about application deployment, but I fear this gives people wrong impressions and makes the mistake of treating an emergent property as if it were a fundamental.