Why does the tool not exclude placements on 'youtube.com'?

Google does not allow placement exclusions for any URL associated with a Google domain like youtube.com or mail.google.com (Read more). Therefore, the tool will not include these URLs in its exclusions list.

However, it's important to note that placement exclusions for specific YouTube channels are not restricted, and the tool will work with them as intended.

Does the Smart Exclusions Tool work for Performance Max Campaigns?

Yes, the Smart Exclusions Tool does function for Performance Max Campaigns. The tool adds all exclusions as Account-Level Exclusions, not to the Shared Placement Exclusions list. Performance Max Campaigns consider all placement exclusions added at the account level.

However, it's important to note that the tool cannot analyze a PMax campaign to identify exclusions specific to that particular campaign.