Reasons? (sincere question, not challenging)
Like I said, I haven't actually read the bill itself, but I have read about it, and from legitimate news sources, too, not just internet randos. So I am trusting the information is accurate, but if it turns out to be not, please know that there was no intent on my part to deceive.
From what I understand, the bill contains provisions that impacts the privacy rights of Canadians, such as making much easier for Canada Post to legally open/read your mail. The bill also contains provisions to increase police powers, which they have been asking for for years, such as the ability to get data related to your IP address without a warrant. They will also be allowed to ask online service providers to release your personal data voluntarily (ie- again without a warrant), and it protects the service providers from being sued if they do so. It expands the ability for our intelligence agencies to share information with the US. Additionally, it supposedly gives CBSA new search & seizure powers, although I have been having difficulty finding details on what that means, exactly. Oh, and apparently it would make it illegal for online service providers to publicly disclose any information regarding vulnerabilities that could lead to data breaches?
I know that immigration is a sensitive issue right now. Personally, I am still a strong believer in welcoming refugees into our country, although I know that is not as popular an opinion as it once was. On that front, the bill will make it almost impossible for asylum seekers that have been here for more than a year to have their cases heard, which means most of them will be deported, potentially back into dangerous situations. It also gives the federal government the new power of the ability to "mass cancel" previous issued immigration papers. I don't know the full details on this, but anytime you're doing something en masse, you're probably not looking at the individual situations, so this seems like it could lead to a lot of bad outcomes for a lot of people.
Basically, I feel that most of the provisions in this bill are things that wouldn't be out of place in a bill introduced by the Conservatives. Admittedly, I am probably more on the left of the political spectrum, but Carney seems to be moving the party more rightward than I am personally comfortable with, hence my disappointment. Everybody's individual mileage may vary.