It doesn't necessitate irrational thought. Moral panic about an invasion is rather rational from the perspective of the nationals in the invaded country. The point that this particular moral panic is "premature" is still a potentially valid criticism. And to answer the question posed above:
> Is being upset about Ukraine being invaded a moral panic?
Yeah, actually, sounds like it[0]:
> A moral panic is a widespread feeling of fear, often an irrational one, that some evil person or thing threatens the values, interests, or well-being of a community or society.
> Is being upset about Ukraine being invaded a moral panic?
Yeah, actually, sounds like it[0]:
> A moral panic is a widespread feeling of fear, often an irrational one, that some evil person or thing threatens the values, interests, or well-being of a community or society.
[0]: https://en.wikipedia.org/wiki/Moral_panic