Why do some investors pay for real-time newswires when the news is likely priced-in by the time it is read?

I don't think retail traders/investors are able to trade on news, because the news is probably priced-in by the time it is read by a human.

Your assumption that it is all priced in is incorrect. Not everything rises (or drops) with the news release nor does price instantaneously gap up/down to its new price and then level out in the seconds after the news is released. News isn't always binary.

I'm not going to chase around for looking for some spectacular examples so here's a more modest one that I observed this week. Kohl's (KSS) made a positive news announcement Tuesday morning. The stock rose 10% fairly quickly and then retraced a bit during the day. For the next three days it gradually rose nearly another 20%.

So without the news, how would one know that there was an opportunity to invest or trade this stock, which in this case, was profitable?

In addition, per your premise that institutional investors use computers to parse news articles in milliseconds, from Wednesday to Friday, where was their edge in this?