This has a file infra/ec2.tf which should be excluded by all pre-commit hooks.
You'll notice it for sure is excluded by trailing-whitespace and end-of-file-fixer because it has both trailing whitespace as well as a bunch of newlines at the end of the file.
Now run pre-commit run -a and you'll notice everything will say Passed
Now uncomment the pre-commit-terraform section in .pre-commit-config.yaml and run pre-commit run -a.
You will notice that even though ec2.tf should be skipped terraform fmt was definitely ran against it.