Why can't region and account ID be empty for SQS ARNs?

S3 bucket names are unique across all accounts and regions, which means you don't need to specify the region or the account ID. For S3 buckets, you can use the following ARN without issues: arn:aws:s3:::bucket_name. This will apply the ARN to a single bucket with name equal to bucket_name.

However, SQS queue names are neither unique across accounts, nor across regions. That means you either need to specify the exact region or the account ID, or use the wildcard * character, which means the ARN applies to all queues with the same name. I used arn:aws:sqs:*:*:queue_name to apply the ARN to all queues with name equal to queue_name.