Again, that's not a question we can answer definitively. That's a question to ask the Public Prosecution Service of Canada.
Keep in mind that the Anti-terrorism Act came into force in December of 2001. Any act that would be prosecutable under that Anti-terrorism Act would have to take place after December of 2001. You would have a retroactivity problem for events that predate that time.
I mean, that might be one reason. The other reason may be that the facts available to the prosecuting authorities wouldn't be sufficient to actually secure a reasonable chance of a conviction.