Because it was libre, or because it was (is) gratis?
I know that I downloaded and learned Terraform because it was free of charge only. I honestly didn't care and I didn't know about its specific licensing status. I was able to quickly and easily install, configure, and run it because Hashicorp made it available as a free-of-charge download. Period, full stop.
Compare it to VirtualBox, which is clearly not F/OSS, but gratis to download and use. In fact my employer mandates our use of VBox, so we all download it, irrespective of license terms. It's extremely popular, even outstripping qemu and other libre VMM implementations.
I know that I downloaded and learned Terraform because it was free of charge only. I honestly didn't care and I didn't know about its specific licensing status. I was able to quickly and easily install, configure, and run it because Hashicorp made it available as a free-of-charge download. Period, full stop.
Compare it to VirtualBox, which is clearly not F/OSS, but gratis to download and use. In fact my employer mandates our use of VBox, so we all download it, irrespective of license terms. It's extremely popular, even outstripping qemu and other libre VMM implementations.