Ah, ok, got you now.
In this case I think excuding will work only by NodeAliasPath, not by type.
<ExcludedCodeNames ObjectType="cms.document">/Blog1/%;/Blog2/%</ExcludedCodeNames>
And I think the main reason for this is the following. Imagine this structure:
If you exclude only Blog page type and leave blog posts to be serializable, this will bring an error during the deserialization. As the target system will not have a root node (Blog) hence it will not know where to insert child nodes. So I think NodeAliasPath with wildcard is the only option available for you.