What a lot of people don't get about analogies is that they're not about a general equivalence between the two sets of things being compared. They're a logical framework for highlighting an important aspect of an argument.

A:a is analagous to B:b, but it's also analagous to tree:sapling or adult:child. One is bigger than the other. That doesn't mean making such an analogy is anything like concluding that 'A' is therefore an adult and 'a' is therefore a child.

If you said Holocaust:US border is analogous to A:a, therefore it's not a big deal, I'd say it's a perfectly valid analogy, but that you've drawn a poor conclusion.