They definitely can bring newly acquired handguns into the country, just not legally. They never had an issue getting them in illegally before, and certainly do not now since the government has taken no action to stop illegal guns. They only care about the legal ones.

And the rate of gun crimes in Toronto keeps going up, all of which are with illegal guns, most of which are smuggled illegally from the US. Below is a link that references some of that data. It should be noted that the rate plateaued a bit in 2020 and 2021 due to lockdowns but are way up so far this year:

https://torontosun.com/opinion/columnists/goldstein-gun-violence-in-toronto-is-skyrocketing-again

If you think about it, this policy is akin to trying to ban swimming pools because of an uptick in lake drownings.