Question

Berakhot 19b:
Come and hear: “and hide yourself from them” — sometimes you hide yourself from them and sometimes you do not hide yourself from them. How so? If he was a priest and it was in a cemetery, or if he was an elder and it was beneath his dignity, or if his work was worth more than that of his fellow — therefore it says, “and hide yourself from them.” Why? Let us say: “There is no wisdom, no understanding, and no counsel against the Lord.” The case there is different, because it is written, “and hide yourself from them.” And should we learn from it? We do not derive ritual prohibition from monetary law.
Come and hear: “And for his sister” — what does this come to teach? If someone was on his way to slaughter his Passover offering or to circumcise his son, and he heard that a relative of his had died, one might think he should return and become impure. Therefore it says: he shall not become impure. One might think that just as he does not become impure for them, so too he does not become impure for an unattended corpse. Therefore Scripture says, “and for his sister” — for his sister he does not become impure, but he does become impure for an unattended corpse. Why? Let us say: “There is no wisdom, no understanding, and no counsel against the Lord.” The case there is different, because it is written, “and for his sister.” And should we learn from it? Passive omission is different.
In these two cases, the Gemara answers that we do not learn from that case for some specific reason (we do not derive from monetary law, and passive omission is different).

Why not say that there really is a general rule teaching that human dignity does not override a Torah prohibition (“There is no wisdom,” etc.), and simply say in both cases that there is a verse stating that this is an exception (“and hide yourself from them,” “and for his sister”)? Then we would be unable to learn from there to another case, because that verse is speaking specifically about that particular case.