Please show where the article mischaracterizes Shh. It describes manipulation of the gene's expression and the results. Shh is involved in the determination of cell fate and embryonic patterning during early vertebrate development.
When the article states that:
and the whimsically named sonic hedgehog (Shh) – were found to result in new feathers.
Sonic hedgehog does not produce feathers in other species, it produces feathers only in those species whose organisms have other DNA which does produce feathers. It has many purposes:
Sonic hedgehog gene transfer may hasten hair regrowth after chemotherapy. From: here
Sonic Hedgehog shapes the brain here
Sonic hedgehog (Shh) is a signaling molecule that is important for defining patterning in the developing vertebrate central nervous system. From: here
a gene called Sonic Hedgehog is used to control the formation of nerve cells called ganglion cells in the eye. From: here
It not only does different things in different species but it even is used to make different features in the same species. So yes, the implication made in the sentence I quoted above from the article is totally false.