The UK stopped capitalising every word in headlines back in the 1980s maybe earlier. It looks much nicer and is more readable. The bold tells you it is a geadline. US newspaper graphic design seems very retro to me.
Local style guide says not to capitalise headlines, presumably.
Though you are right, the general rule here is not to change headlines and that should probably apply to style as well as wording. Looking at other posts on the main list there seems to be a mix as the original styles (sentence cap, all words capitalised, all but articles, …) have been kept.