Is it acceptable to use proprietary software (platforms) to promote software freedom?

[Adonay Felipe Nogueira]

Indeed.

I also agree with this.

As a subject for another topic, here are other analogies that don't
quite work as we'd expect:

- "Non-free software is like slavery". However, it isn't, because the
  user still has the ultimate choice of not using the non-free software,
  no matter how much the switch will cost.

- "Software is absolutely equal to cooking recipe". However this doesn't
  work because who/what "consumes" the software is the computer, and it
  does so blindly (without questioning). Besides, when "consumed" there
  is no loss of that particular copy of the software, that is, that
  particular copy will still exist.