Quote: "B-1 or B-2 Visas: During your visit to the United States, you may visit Canada or Mexico for up to 30 days and re-enter the United State, if you re-enter within the timeframe indicated on the Form I-94 that you received when you first entered. "
Quote: "B-1 or B-2 Visas: During your visit to the United States, you may visit Canada or Mexico for up to 30 days and re-enter the United State, if you re-enter within the timeframe indicated on the Form I-94 that you received when you first entered. "
This means you can re-enter the US after a 30 day visit. It's clarifying rules for entry into the US. It has nothing to do with whether you are allowed to enter Canada or not.
Canada and the US are separate countries. A B-1 / B-2 does not allow you to enter Canada.