Earlier quoted context omitted.
If previous sales were about the same numbers, it's a perfectly fair way. Impressive, amazing numbers maybe, but still stagnant, if they didn't improve over the last ones.
Stagnant has a very negative meaning attached to it. The author could have used words like "constant" (neural) or "steady" (positive). He chose to use "stagnant" and deserves to be called for it.
Stock price plummeted after the results, and I doubt market analysts were influenced by that specific article.
The market clearly agrees on the assessment that the sales are "stagnant", negative connotation included. Which is not surpising since the stocks are priced taking into account potential growth, rather than present results.
"Constant" or "steady" I would expect from Apple PR wording...
(And I have no beef with Apple, my brother works there and I'm a satisfied customer, for all that matters).