That's the whole point of anger towards them. Thats dirty money. That's money laundering. They don't pay income/corporate tax in Canada.
You're completly ignoring the massive subsidies and currency devaluation to keep this scheme going. If we didn't have import tariffs all our local industries would get destroyed because nobody can compete with someone who sells their goods below manufacturing costs for decades.
If I retire and moved to Canada with $10m (I wish), how much tax would I have to pay at the border? Would it matter which country I'm moving from?