I don't think they have any problem. They would like us to keep correspondence to a minimum. I personally think Canadian high commission / visa offices are the most flexible of all I have seen. Otherwise, for other visa applications for e.g. UK or US or Australia, once you submit your documents, you don't hear from them until they make a decision on your file. You cannot send additional documents. They don't even invite people for interview if they have any doubts. They simply refuse application. And the best part about Canadian PR process is that they charge fees only if an application is complete.
For all other embassies / visa processes I have seen, they charged you the processing fee before they look at the file. I think they are fair in telling us that the whole immigration process is complex and time consuming. All applicants need to have patience otherwise they shouldn't have applied in the first place.