Most of those, such as Denmark, Norway and Sweden, have very strong unions which essentially guarantee a minimum wage for everyone without legislation.

Denmark has a $16 per hour average minimum wage and Finland and Sweden has a collective bargaining rule, even if you are not a union member and it is illegal to do anything anti-union.

The person you responded to talked about minimum salaries which those places absolutely do have, even if they don't have a minimum wage.

The Scandinavian countries have de facto minimum wages because the unions have actual power there.