Canada's official numbers do show that Q3 2022 was a record high for emigration (16.5k -- Q3 2018 was 15.5k), but other recent quarters (Q4 2022, Q1 2023, etc) are still lower than prior years. And you have a significantly higher population now than back then.[1]
[1] https://www150.statcan.gc.ca/t1/tbl1/en/tv.action?pid=171000...
A very important detail here is that Software Engineering is a specific specialization under the Engineering faculty. This figure does not include Computer Science graduates, for example, as that is a separate and much larger department.
So, this is a poll of 87 students (out of ~107) of a very specific graduating class. To put this in perspective, the Computer Science department at Waterloo is 4,000 undergraduate students.[2]
I'm not refuting that Canadian graduates often look to the US for better employment opportunities (full disclosure: I did that), but I think we owe ourselves to look at this topic objectively.
[1] https://uw-se-2020-class-profile.github.io/profile.pdf [2] https://cs.uwaterloo.ca/about/quick-facts