Not subject despite が?

Question

I've come across the following dialogue:

「シグナムはお風呂どうします？」

「私は今夜はいい。明日の朝にするよ」

「お風呂好きが珍しいじゃん」

An unofficial, but to my mind high-quality translation offered something like

"That's rare for a bath-lover like you."

for the last the line, and going by context, that's the only right translation I can think of.

However, going by grammar, wouldn't it translate to

"Bath-lovers are rare."

?

Of course, this statement feels out of place and is also not true (there are plenty of bath-lovers).

My Japanese friend translated it to

"You are rare."

claiming that お風呂好き would directly refer to シグナム.

He interprets が properly (as a subject marker), but it sounds even more wrong.

Assuming that the unofficial translation I provided first is correct, why is が used, rather than something like にとって? Wouldn't you normally use にとって to express those kinda things?

Answer 1

A:「お風呂好きが珍しいじゃん」
B:「お風呂好きがお風呂に行｛い｝かないのは/お風呂に入｛はい｝らないのは珍しいじゃん」

"A" is an abbreviated expression from "B".
In this case, the substantial contents of the phrase itself is omitted. This kind of abbreviation is frequently used in daily conversations like:

1-1 あなたのようなお風呂｛ふろ｝嫌｛ぎら｝いが珍｛めずら｝しいね。
2-1 お風呂嫌いが珍しいね。
3-1 勉強{べんきょう}嫌いが珍しいね。
4-1 お肉｛にく｝好｛ず｝きが変｛へん｝だね or お肉好きがおかしいね。

These abbreviated expressions correspond respectively to the following perfect expressions like:

2-1 あなたのようなお風呂嫌いがお風呂に入るのは珍しいね。
It is unusual for a person who dislikes a bath like you, to take a bath.
2-2 同上｛どうじょう｝ Same as above
3-2 あなたのような勉強嫌いが（今日｛きょう｝に限｛かぎ｝って一所｛いっしょ｝懸命｛けんめい｝）勉強するというのは珍しいね。
It is unusual for you, who usually don't study, to study (hard only for today).
4-2 あなたのようなお肉好きが（今日に限って）お肉を残｛のこ｝すのは変だね/おかしいね。
It is strange for a meat-lover like you to leave the meat behind (only for today).

These abbreviated expressions are used more than perfect ones in everyday conversation, and the latter ones are taken even verbose.

After these study, I could say only C is correct but the rest are incorrect among the following attempts shown in your question.

C: "That's rare for a bath-lover like you."
D: "Bath-lovers are rare."
E: "You are rare."

I feel sympathy for non-native people studying Japanese, because in addition to frequent abbreviations of subjects in Japanese, there are omissions of such an important part in a sentence like this case.