A very pertinent point. May I address it for you?
You are most correct in saying that (generally speaking) Japanese have traditionally been turned off by the smell of sheep. Yep, sheep - meaning mutton (adult sheep). Old sheep (mutton) smells. They have little understanding of lamb (baby sheep).
In fact, when I ask Japanese people whether they know the difference between lamb & sheep - they have no clue whatsoever. ‘Gourmet’ Japanese (what we call foodies) know & they love it as much as me. In fact, I hosted a party around a decade ago at my joint & I cooked (lamb) for 10+ punters. Happy to PM you a pic. Their smiles filled my heart with joy.