I think the printer example is wonderful and exactly the kind of material you
need to explain the practical side of free software. It's how the problem
manifests itself. And even though it might've originally happened 30 years
ago, we have even now a new thread on the forum about problems with a
printer. I believe some people can and do relate.
I think people dislike Stallman because he makes them think about computing
from an ethical viewpoint. People don't like it when you say that instead of
blindly using whatever they get in front of them they should evaluate the
implications of using the software. For themselves and society at large.
And these lazy people start reacting badly and throwing around all kinds of
ad hominems to avoid the actual issue. Such is human nature sadly. But as rms
has said, there will always be people you cannot convince and you shouldn't
waste time trying to do the impossible.