Some of these "issues" boils down to personal settings.
Some may want watcher swallowed and some may not. Sawllowing takes up space that could be used for the display of other tasks.
I don't really want to try coding for every possbile window manger extension with the base scripts.
Nor should base scripts be expected too.
The scripts in your home directory should be available for your custom and additional settings. We also have fluxbox, openbox, hackedbox, icewm, window makers, and still others.
The extensions should play nice with the OS and not the OS try to accomodate every possible window manager.
I would think it cleaner to remove or comment out the jwm swallow statement,
Letting the use decide to comment out .xsession and uncomment jwm swallow statement.