What were the post-war tensions in Canada, and how did these lead to the Winnipeg General Strike in 1919?

After World War I, Canadian soldiers returned home to find very few jobs waiting for them. This was mostly the result large numbers of immigrants who came to Canada during the war to work in the country's industrial sector. The massive unemployment that these former soldiers experienced caused a lot of social unrest. Many blamed immigrants for the lack of jobs and anti-immigrant feelings rose. The war also caused significant inflation in Canada, which increased the poverty rates of the country making it difficult for many to maintain an adequate standard of living. All this occurred while the bosses of industry reaped a lot of profits from war time manufacturing.
Anti-Bolshevik sentiments were also very strong in Canada. The Russian Revolution of 1917 presented a real fear that revolution could spread to Canada as well. Many of the new immigrants to the country were looked at with the suspicion that they might be instruments for a Communist revolution. Furthermore, workers looking to unionize were often branded as Communists.
All this contributed ill feelings between labor and management, particularly in Winnipeg's building and metals sector. The workers at various companies in these industrial sectors attempted to form a single union in 1919. When negotiations fell apart with the managers and bosses in Winnipeg a general strike was called on May 15. This strike was joined by employees in the public sector too.
https://www.thecanadianencyclopedia.ca/en/article/winnipeg-general-strike