Why just for us? On the other hand we provide all police declaration form officially
It's not just for you. It's for everyone. The process is the same for everyone. IRCC doesn't just accept the police certificate, they also conduct further reviews to confirm your background and complete the security clearance. Again, they do this for all applicants. Any delays are due to your country of origin (or a country you've lived in) being slow in providing the information Canada needs to finalize your application. Once again, the process is the same for everyone. Your country is extremely slow to respond and this is the reason for any delay in background or security checks.