none of this justifies a nasty mean spirited blog post.
I see it like this: Anthropic saw an opportunity to make a splash. Jarred made it happen without directly disparaging zig, but the implication is that zig couldn't cut it. Andrew made it more personal.
(As for Anthropic's motivation: only they know. But I suspect that they saw Zig's AI policy as a potentially existential risk, and moved to de-risk their position. That is a technical decision, just not one rooted in the merits of any particular language.)
Regarding zig becoming a risk: that's a reasonable line of thinking that I hadn't considered. I don't know how likely it is that zig will fail to progress and fall behind as a language compared to others that are assisted with AI, but it's a possibility.