That's because you don't watch the CFL so you don't know the difference. That's true to probably anyone else who dismiss the CFL.
It is true that most CFL players are players who couldn't establish themselves in the NFL.
Truth is, CFL and NFL are different. CFL is a quick passing game and NFL is a slow running game.
Therefore, the tool set needed in the CFL and NFL are a bit different. The main difference would be size, you don't need as big of a linebacker, you need a linebacker that can both stop the run game and stop the passing game and that often requires speed.
The second big difference, the field is wider and longer so you need a QB with a stronger arm that will throw a huge pass every few minutes.
For those reasons, a common end result in the CFL will be something like 34-31 while a common result in the NFL will be 17-13.