As noted, because of the First Amendment, such designations aren't as common in the United States. The designation by Canada means not only denying entry to members or associates but also criminalizes anyone associated with fundraising on behalf of the Proud Boys group, resulting in fines and seizure of assets. The same as they do with anyone associated with al-Qaeda or ISIS, or other terrorists.
Source: CBS News
Canada on Wednesday labeled far-right group the Proud Boys a terrorist organization, less than a month after some of its members participated in the deadly U.S. Capitol riot. Canada's public safety department said it had "reasonable grounds" to believe the Proud Boys is a group that "has knowingly participated in or facilitated a terrorist activity."
"The group and its members have openly encouraged, planned, and conducted violent activities against those they perceive to be opposed to their ideology and political beliefs," the public safety department said.
The label puts the Proud Boys on the same list as militant groups like the Islamic State and al-Qaida. The Canadian government even added several Islamic State and al-Qaida affiliates to its terror list on Wednesday in addition to the Proud Boys.
Under the new classification, it is illegal in Canada to give logistical or financial support to the Proud Boys. Canadian financial institutions must freeze assets tied to the group, and anyone associated with the Proud Boys can be denied entry into Canada. The listing also allows the government to seize Proud Boys property, and supports removing Proud Boys content online.
The U.S. doesn't have any such designation for domestic groups, and has to rely on other methods.
Canada has labeled the Proud Boys as a terrorist organization, but the U.S. doesn’t have a designation for domestic groups. Alexis Collins, former counterterror official at DoJ, says despite that, “there are other types of tools we can use.” #velshi pic.twitter.com/hWm1SApxiI
— Ali Velshi (@AliVelshi) February 6, 2021