This is quite sad. I'm also curious how projects that integrate Terraform, such as the OpenShift Installer will deal with this. I'm pretty sure there is at least one project in that ecosystem that spins up OCP instances on demand. I wonder if Hashicorp would consider that competing...
Found the important part in the terraform license, for anyone else interested:
> Additional Use Grant: You may make production use of the Licensed Work,
provided such use does not include offering the Licensed Work
to third parties on a hosted or embedded basis which is
competitive with HashiCorp's products.