[nhaehnle]

Based on Kahneman's Thinking, Fast and Slow, I would suggest that it is a case of substitution: We (often unconsciously) substitute a hard question for an easier question. In your examples, that might be: Did you have good experiences with immigrants? How do you feel about war more generally?

Those judgments aren't necessarily bad in themselves. For example, as a pacifist, I might be happy to err on the side of non-interventionism as long as the situation is sufficiently unclear.

These substitutions only really become problematic when we close ourselves to new data that might change our mind.