As long as people can choose not to use the language, and I'm up front about the limitations, then yeah it seems fine. If I wrote a programming language that couldn't blow up the earth, I'm happy saying people need to find other tools if that's their goal. I'm under no obligation to build an earth blower upper for other people.

There are programming projects[1] out there that use licenses to prevent people from using projects in ways the authors don't agree with. You could also argue that GPL does the same thing (prevents people from using/distributing the software in the way they would like).

Whether you consider it moral doesn't seem relevant, only to respect the wishes of the author of such programs.

[1] https://github.com/katharostech/bevy_retrograde/blob/master/...

it's your language, do whatever you want. unless you're forcing others to use that language, there's zero moral issue. obviously you could come up with a number of what-ifs where this becomes some monopoly or the de facto standard, but that's not what this is.