You have created Supplier and Tax Authority for a particular Business Partner. When you try to block the status of the Supplier, the status of the Tax Authority and the Business partner is also getting blocked.
The Supplier and Tax Authority are the Roles of the Business partner and the status is completely dependent on the roles of Business Partner.
This is the general system behavior.
So, if you block the status of Supplier, it will block the status of the Tax Authority and vice versa. This will also block the status of Business partner.
In general, if you try to block a status of one a Business Partner role a Business Partner then all the roles will be blocked.
KBA , AP-RC-BCT , Business Config. Tools (SAP Business ByDesign , Product Enhancement