Lamrim is contrived compassion
Trekcho is real compassion
Whats so controversial?
What a ridiculous line of argument!
The capacity to walk is also innate in humans, yet a child must learn to walk. Merely showing it what walking is does not suffice.
I don't think this is really any different from what standard Mahayana says about relative bodhicitta vs ultimate bodhicitta. One is contrived while the other is not. However, I'm not sure what Sonam is on about when he questions if dedicating one's life to helping sickly people is "true compassion." I don't think there's any doubt about it. While it's true that the uncontrived and inseparable wisdom and compassion of a Buddha--which is what all Mahayana practices aim at revealing--is certainly better because it is purely spontaneous and shaped by deeply penetrating wisdom, I think we can say that the world would be a vastly better place with more people with "contrived compassion" such as you mentioned.
And until one more significantly opens up one's realization in Dzogchen, I think one is still in need of engaging in contrived "bodhisattva activities" post-session, in everyday life. Certainly one's Dzogchen practice will inform that more and more--given one has actually ascertained rigpa--and probably one's training in compassionate conduct can open up one's heart more to one's Dzogchen practice.
FWIW, though, my impression was that actual issue of "Lamrim compassion" vs uncontrived compassion was actually about making a distinction between mouthing compassion and feeling it on the cushion--away from any actually suffering sentient beings one can perceive--while post-session one still remains self-absorbed, impatient, discompassionate, and stingy when confronted with the needs and suffering of others. I think that any practice grounded in true insight into one's nature--and here I mean sutra, tantra, Mahamudra, or Dzogchen--will send one in the direction of actual compassion.
Now we've spent an awful lot of time arguing about whether or not Dzogchen has an inherently stronger potential to get directly to the heart of the matter than other systems, and I have freely shared my opinion on that matter, but I'd personally be happier dropping that debate for good now. That topic is simply not one I ever think about privately, nor does the prospect of convincing other to adopt my views about how special Dzogchen is give me any satisfaction whatsoever... I've realized I'm thinking much more about how uneasy this strife between us is making me. This Dzogchen vs "the rest of Buddhism" debate has proven to serve no purpose because those who are firmly convinced one way or the other are not gonna budge, and why should they? They're drawn to what works for and makes sense to them and that's great. We'll each just be better off practicing the path that we feel is best for us as individuals and forget about the rest.