Because Roger Ver is among those a few people that really understand bitcoin's potential. Programmers seldom look away from their technical worries, they care about how the car works, but are not able to see where the car is going
The blocksize debate is not a technical issue, it exposed several long existing problem of bitcoin: Mining centralization, development centralization and lack of consensus based decision making mechanism regarding protocol change. And what core programmer is doing is to make these problems worse, their solutions create more and more centralization incentive, especially in R&D. If bitcoin is centralized in the hands of a few guys, government and law enforcement will take down them in a couple of hours, then the whole system will just collapse like e-gold or liberty reserve