When you deny the permissions to Table columns it's only for Table columns. Not views which has been created based on that table.
For example, DBA wants to restrict developers to do changes on a Table. So he deny the permission for that Table & creates a View based on that Table. Now developer can't see anything about Table, instead he could use the View.
Again, DBA wants to show only few columns from View as he don't want to show Log columns like(Created_By, Created_Date, Updated_By, Updated_Date). So he needs to deny permissions for those columns on that View.
So you need to assign things against View too.
DENY Object Permissions (Transact-SQL)[
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