With CRISPR, it took a long time to figure out how to reliably edit just the gene you want and acceptably minimize off-target edits, including by delivering the therapeutic to just the organ affected and getting the dose and release right.
The public is understandably leery about experimental medical techniques. If they had killed this newborn child with CRISPR therapy, then it might have set created a backlash delaying translation of this technique for years, possibly decades.
In biomedicine, we’re always looking for therapies that approximate the level of precision control available in software. Unfortunately, it’s never more than an approximation, and our ability to measure and predict the size of that error is always limited. That is why the field moves slowly.