Interesting thesis, with a couple of flaws.
Each step in the "universalization" of empathy that is given as a past example also included maintaining a sense of "otherness" along with a sense of "self" and "belonging." That this is me, this is us, that is them. I.e., no particular step lacks the "them" picture.
It is therefore not necessarily the case that the process ends with everyone as an extended family. As long as resources are limited and there is competition for resources, should any part of the "extended family" feel that they aren't getting their fair share, they will split off, create their own identity, and work against those with whom they originally identified. I don't believe it's possible to understand human history without understanding this "split off" process along with the "come together" process. The speaker doesn't consider it at all in his presentation, even in his religious examples, where such splitting and coming together happen all the time.
Technology allows the extended families to be "bigger," but it is a dynamic process of coming together in some ways and splitting apart in other ways, simultaneously.
Or, more succinctly, those you want to join you in your vision of togetherness in the world, your version of what is good for yourself and humanity as a whole, may actually have a different vision of what is good for oneself and the world and not want to join you in your efforts. Indeed, they may not merely be anarchists and rebels, or selfish people full of avarice and hatred: they may well have their own vision of which you don't approve, and wish to incorporate you into their version of universal kindness against your will.
This is all well and good. A valid point.
I agree that if it's an inherent dichotomy, us/them, then, for
us to exist, we can never escapegoat a
them.
However, I think you're (dis?)missing the primary direction this thought is
supposed to provoke. A thought that provokes
change.
My perspective/reaction to this video:
As some bald dude said one time,
be the change you wanna see.
For me, when perceiving these kinda messages, I try to stay rational, yet, optimistic. Hopeful (?).
I don't get too caught up in always analyzing a
conceptual system/a theoretical thought for why it
won't work [there's always limitations, huge ones even]. However, at least,
do something about it - move towards a direction
you wanna see.
If you believe in the inherent message, the
sentiment, this video is aiming to evoke/provoke - a call to action for the collective human condition/conscious (Fe?

) - if you agree that it's for a positive sum benefit towards preserving this earth, for as long as
we can, why not do it?
Make an effort, in whatever sphere of one's own influence in their slice of earth, to portray the sentiment of this video into
action.
Some core principle: don't be greedy. It unbalances, and then, chaos ensues to mass disorder, in order for balance to be restored once again. Cycle. So, in whatever sphere of control you have, be
preventative, if you have foresight at your disposal. Exercise to preserve the balance.
Don't take more than your piece of this earth, more than you
need. However, our archille's heel as humans is this urge to
want.
We are shackled by our abstract cognition - we have, to such a degree [that no other
life-forms do], a drive to
want.
Supercedes need. Less primal. More calculated. Slippery slope - greediness. And, we often justify a want as "need", to ourselves. Or that we've got...."priviledged mind"

sick

...so thus we're justified. So if your mind is so priviledged, then don't abuse that
priviledge.
In order to achieve this:
Us against Them -> You against me.
needs to become....
Us and Them -> You and me
I [Understand->empathize->respect] You.
Granted: Differences cannot exist without discord AND harmony. However, why not just up the odds towards harmony more*?
* At least, for as long as, we, the collective lifeforms on earth, can [i.e., barring natural disasters and such].
^ may sound hippie, but, again, why
not?
To add: The title of this vid - "civilisation" - how ironical.
V Peguy: exactly! So let's all together see that it converges on a net positive front.