A is fine
but B is not
if it’s ~ then it is ok，but ~ is not
Structure
- Phrase 1 + ならまだしも Phrase 2
しも is from classical Japanese and emphasizes まだ
[Phrase 1 is acceptable/permitted, but Phrase 2 is not acceptable/too much/strange・Often used with くらい]
Judging from nihongosensei.net, this phrase seems to be interchangeable with ～ならともかく (which I just encountered in the wild). I’m wondering if ～ならともかく should be added to the SRS in some form.