So far I haven’t seen an argument in this thread for why it’s bad reasoning when you want to show that the reasons are not what’s stated. It was just stated that it’s bad. So why is that?
Somebody states that they think X because of Y, and they don’t say anything else (Y can be also a group of reasons). You show an analogy where Y would cause Z too (provided the logic is solid). The other party states that they think differently about Z - the reason doesn’t matter.
In this case, either Y isn’t important at all, or there is also something else besides Y, which is not stated. In other words, X is not because of Y logically.
I don't see a problem or a point. A cause can have more then one effect, a logically sound analogy doesn't make all analogies logically sound. And producing causal arguments is inherently hard, we've spent centuries holding irrelevant things as fundamental causes of phenomena, and we still don't know fundamental causes for most observations we have produced.