I don't often use wiki but this is a relatively good summation so I'll use it. Dino was referring to this. He was not insulting you with the term: the genetic fallacy.
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The
genetic fallacy (also known as the
fallacy of origins or
fallacy of virtue[1]) is a
fallacy of irrelevance that is based solely on someone's or something's history, origin, or source rather than its current meaning or context. This overlooks any difference to be found in the present situation, typically transferring the positive or negative esteem from the earlier context. In other words, a fact is ignored in favor of attacking its source.
The fallacy therefore fails to assess the claim on its merit. The first criterion of a good argument is that the premises must have bearing on the truth or falsity of the claim in question.
[2] Genetic accounts of an issue may be true, and they may help illuminate the reasons why the issue has assumed its present form, but they are not conclusive in determining its merits.
The article goes into further detail if you care to read it.