The registry was a political powder keg right from the start. Those who opposed it did whatever they could to make its implementation as inefficient and expensive as possible, and then framed the entire issue as being about the cost of implementation. Canadians who didn't bother to read the details of what was going on - such as the many who rely on 90-second radio news clips for their understanding of the world - formed the opinion "Gun Registry = Bad". Canadian police have been saying for years that the gun registry is not only not bad, but essential for saving lives. That hasn't resonated as much as the Conservative malicious PR campaign. The irrationality of the argument is apparent now that the money has been spent to implement the registry, so why close it down based on the cost of implementation?
We have reached the point where it's near political suicide in some regions to support the registry, and consequently parliament is stepping through the process of dismantling it. I suspect that Liberals supporting the dismantling are like Democrats voting for the Iraq war... in the face of such strong public opinion politicians can't always vote their conscience. (Or who knows; maybe some have bought the anti-registration PR campaign too.) Our representative system is a mix of leading the public and following the public. Sometimes the latter is unavoidable. Sometimes that really sucks.