Show a block if the page content has a specific taxonomy term
You need to add two contextual filters to your view block:

Important: Use this block (override) for all these settings.

Content: Nid 


Provide default value: Content ID from URL

More:check: exclude.

This contextual filter will exclude Brand X from the list if you're visiting Brand X page.

Content: Has taxonomy term ID 


Provide default value: Taxonomy term ID from URL

check:  Load default filter from node page, that's good for related taxonomy blocks. 

When the filter value IS available or a default is provided:

Override title: Type here your block title using %1 for the first argument, %2 for the second, etc.

This contextual filter will list all your brands from current visited Product type