Hi Sarah-anne,
Essentially there is nothing new about what this video says, and it just says what plenty other paleo bloggers and experts have said: you start with the basic blueprint and then you adapt it to yourself. I mean, check out Mark's posts on potatoes, dairy, and carbs; also check out this post here by archevore about being too evangelical: http://www.archevore.com/panu-weblog/2011/2/28/proof-that-orthorexia-exists.html
The thing about this video is that the speaker is talking about a DIET, rather than a lifestyle. And - just from watching that video - I'm also not sure if he's well informed about Paleo or whether he is lumping it into a general low-carb category with Atkins, Zone, and the rest.
Paleo is NOT a low-carb diet - its a lifestyle based on eating unprocessed, mainly pre-agricultural traditional foods. It starts out as low-carb because that's needed to reprogram the body from burning sugar to burning fat for fuel. So if you're overweight, metabolically damaged by the SAD, you initially go low-carb paleo to reverse the damage.
After that, you focus on unprocessed, whole food rather than macronutrient counts. The human body is quite good at adaptation, and will soon grow to tolerate low/very low carbs, which leads to what we know as plateau; a lot of low-carb dieters eat low carb simply for its own sake - I mean Atkin's bars, low carb cookies, dreamfields pasta - its junk food, just one that's low carb.
Now to the idea that you get 'married' into this idea of a paleo lifestyle; its true that a lot of people get attached to the paleo identity, and that isn't a bad thing, since paleo is meant to be a natural lifestyle, close as possible to the one people evolved on. However, I don't think that is what the speaker is talking about; what he is referring to is people who get so attached to paleo that they become more concerned about following the dogma than health, and refuse to consider evidence that may force them to re-evaluate something they held for true.
Mark actually talks about this all the time - that we should take advantage of science (check out 'when science trumps Grok' - sorry I can't link to it, MDA is 'under construction'). It's the case with things like dairy: don't avoid it just because its post-agricultural - I'm going to give the dairy example again - studies show that dairy fat can be very beneficial, so you have to see what it does for you personally; some folks benefit from fermented, raw, full fat dairy (e.g. me); some find it causes problems. If you're in the latter group, avoid it; but don't write it off simply because it doesn't fit the timeline.
So the bottom line is that you have to adapt it to yourself rather than consider it something set in stone. Some people fare well with continuing on very low carb (see Peggy Emch); some people are fine with extra starch, and eat sweet potatoes, even wild rice; the point, however, is eating whole, unprocessed, mostly pre-agricultural food; thats a very broad and adjustable template, with which you really can't go wrong, or into 'disbalance.'
Hope I helped!
Don't worry be happy!
Lots of Paleo love,
Milla :-)