It was fair that Canada and Canadians frequently made this observation and we should best considered it as North American.
这是一个很明显的宾语从句,"North American"作为从句中的宾语,“this observation”作主句中的宾语.写成陈述句就有两个主语了,一个是“Canada and Canadians ”,另一个就是“we”（这个原句省略了,但翻译的时候要译出来）.不知道你能否理解!