Let us talk about Adamson BBQ in terms of the law and not emotional opinion on pandemic risks. What makes his protest any different than protests in the street where nobody was arrested?

First of all, the notice posted on premises don't state the reasons for the order. So it doesn't comply with s. 22(7) of the Health Protection and Promotion Act.

Charter 2(b) Freedom of peaceful assembly.
This was a political protest. Nobody was forced to be present who didn't wish to be and they did not interfere with citizens who did not wish to be present. (Unlike other current protests which blocked transportation)

Charter 2(d) Freedom of association.
The people who were gathering were free to associate with other people who share similar concerns about the effect of political actions which infringe on their liberty.