Why are the issues status field and resolution field not editable?

Platform Notice: Server and Data Center Only - This article only applies to Excel-like Bulk Issue Editor for Jira Server and Data Center

You can transition an issue from the context menu. The status field is not supported for editing directly.

The resolution field is supported under the limited configuration environment.

You can edit resolution field by placing the field on 'Edit issue screen' but you should not usually add the field on the issue screen.

We recommend this operation for maintenance purpose only (ex: bulk editing after csv import).

Please see the below documentation for more detail.