You can configure this behaviour today. Search for "policy-rc.d". IMHO, it's a bug in configuration management tools that they do not arrange this by default.
I think Debian's rationale is that if a sysadmin interactively installs a package, then that sysadmin does so to get its primary service (if any) running, so packages should arrange this by default.
> but it's bad as an overall practice.
I agree with you, but only in the case of non-interactive use. Different use cases demand different defaults. Tooling should be able to make the appropriate distinction automatically. Currently, the tooling does not, but that (IMHO) is a design flaw in the tooling, which Debian does not produce.
In the interactive case, I'm torn, but I do see the logic.
In the general case, then, I maintain that tooling should use policy-rc.d to adjust the default as necessary, and that failure to do so is in the tooling, not in Debian.
> I think Debian's rationale is that if a sysadmin interactively installs a package, then that sysadmin does so to get its primary service (if any) running, so packages should arrange this by default.
Except that if a sysadmin installs a package that provides a daemon, this
daemon usually needs to be configured first, so starting it with semi-broken
config (and debconf-generated one is still semi-broken) is counterproductive.
