I suspect it's not a case of them trying to prevent modding, just that the tools don't exist in the public domain as far as I know. I guess one can remain quietly optimistic that Larian may rectify this either with Divinity 2 or when Divinity 3 is released. I'd like to think so, anyway.
Larian does have the tools, they were just not made in such a way that they would be useable by modders. They were going to look at changing that, but given they have not said anything since then I take it that it would be too much work.
