I emphatically agree that tagging should be automated. Terraform, CloudFormation, Pulumi, whatever - make it part of the code. It's way too easy for someone to miss a tag or misspell a tag if it's being done manually.
100% agree. We've seen some crazy typos and other things while helping our customers clean up their tagging. We're developing Part 2 guide right now, which will cover Terraform and CloudFormation.
absolutely manual tagging stuff is a plague. In large enterprises I've seen manual tagging efforts that result in massive amounts of gaps and confusion about who owns what and whatever else is being done with tags.
Someone's job relies on that automation not existing (half kidding).