I think what they should have said is "there isn't a tool like Helm for ECS" If you want to deploy a full prometheus, grafana, alertmanager, etc stack on ECS, good luck with that, no one has written the task definition for you to consume and override values.
With k8s you can easily deploy a helm chart that will deploy lots of things that all work together fairly easily.
With k8s you can easily deploy a helm chart that will deploy lots of things that all work together fairly easily.