Explanation
Statements and questions are tricky and confusing. When the access is granted for the group (all users) for ALL (each) dashboards and ALL (each) reports in the workspace, then the will have read access to the specific (A, one) Dashboard and several reports, because they are part of all dashboards and reports. There is no statement, that for the other dashboards (except the one) and the other reports (except the several) that access must be prevented. They are also accessible (maybe it is not desired but not stated here).