I could discriminate against Canadians and only work with Americans...but xenophobia isn't a virtue.
I could try to do business with Canadian customers without corporate presence...very difficult because most national governments make it hard for anyone abroad to serve their citizens with goods or services.
Now, multinational corporations are faulted for trying to subvert local cultures and politics. Sometimes they are in the wrong, but mostly they either show the locals a better way to do something (see Japanese car companies in the US) or are resisting outright brigandage, such as governments stealing ("nationalizing") their assets. Individuals can sometimes resist such brigandage effectively, but it is more common that groups of individuals trying to make a living together (corporations) resist more effectively and thus get noticed. The alternative is for companies to roll over, accept losses and simply avoid doing any business with countries which have uncertain political climate. That reduces the quality of life for the locals because they have fewer employment and/or shopping options.
So, hooray for multinational corporations! I like being able to buy Serbian rifle ammunition, Japanese cameras and Mexican avocados.