You do realize that is a "free culture" article you linked and is not
relevant to a "libre software" discussion? Also, just as a disclaimer, since
I'm new to the "troll hole" thread: I am a libre software developer/advocate
and I am vehemently against being grouped in with the "free culture"
movement.
Also note this, OP, humans are complex beings that are able to work toward
similar results without doing so on purpose.
A clear-cut logical answer to your original question is that a movement is
defined by who leads it. In the case of the free/libre software movement,
that would be the FSF. In the case of "open-source movement", that would the
osi. The fact that they are two separate leaderships, which do not agree with
the each others methods, means that no matter how much you whine and moan
about it: they are two separate movements and will continue to be for the
foreseeable future. The actions and overall decisions of the followers of
each leadership do not define these two movements. So until one of these
leaderships defers to the other, there will be two separate movements which
on the surface appear to have the similar results.
If you need that in analogy-form: You can buy a basketball from either of 2
local sports stores. Are you going to say that just because both of them can
sell you a basketball that they are the same store? More to the point, if
buying a basketball from one of these stores will prevent it from going
bankrupt and doom the other store to fail, are you not going to take into
account who is the owner of that store?
The free/libre software movement and the "open-source movement" are not
indistinguishable things that you can substitute for each other because you
think they are the same thing. Each movement is the materialization of the
ideas and philosophies of those behind it. You can no more interchange them
than you can people. Doing similar work does not mean they are the same
person.
If one of those two stores were owned by {insert the worst person you can
think of} and the other was owned by {insert someone of lesser harm to the
world}. Whose store would you buy the basketball from? According to your
argument, it wouldn't matter because they both sell basketballs, so who
cares!~
Personally, I find that type of thinking is irresponsible, but if that's what
floats your boat, then go ahead and ignore logic and while your at it, stay
away from me.