No, absolutely not. Private property is a precursor to free software. I own a computing machine, therefore I have a natural right to control what my computing machine will compute.
> That said, to say it's immoral not to give away the work you produced/paid to produce is ridiculous.
You don't have to give anything away. Free Software means you can share your program with whoever you want, including nobody.
> You're not taking anyone freedom away by providing proprietary software.
That would be true, if proprietary software meant "no source code available" (that's usually called Freeware). But in reality, there are laws like DCMA that actually do restrict your freedom, in a literal sense.