Thinking about it a little more, the same principle works in English:
- I eat someone like you for breakfast!
- I would never date someone like you
- This app would be great for someone like you, who watches a lot of anime on their smart refrigerators
so is “some X like Y” dismissive? Yes and no. Not inherently, but it sure can be used that way.
Same goes for なんか
(and that’s all it is at the end of the day, a contraction of なにか, which is like どこか or どれか etc., a question word + か used as a stand-in for one thing that could answer that question)