In Canada I’ve heard so many people say that their promotions stopped after 45 years of age and they are well educated and current? Is it legal for companies to practice ageism?

Everybody over 18 has the right to be offered the exact chances in employment. Nobody can deny you job training or a promotion or even be forced to retire because of your age. Ten provinces and three regions in Canada have legislation designed to ensure the equality of its people.
Canada’s provisions prohibiting age discrimination are based on the character of Rights and Freedom, which applies to all jurisdictions and governments entities. The federal government and all provinces and regions contain anti-discriminatory legislation against age. Each jurisdiction has a human rights statute that prohibits discrimination based on age. As mentioned above, it refers to everybody over 18.
Employers may not, directly and indirectly, reference age in the job advertisement. The application form should not age questions related to age, and also, during an interview, they cannot ask any questions about your age. Employers cannot limit employment opportunities such as transfer, promotion, and training. Employers aren’t allowed to lay off someone because of age.