Well, now we have to establish the semantics of "a soccer player".
When speaking of an athlete, I assume we're talking about someone who trains and competes as if it his or her profession. As such, I'd be shocked to discover "a soccer player" who eats less than 5000 calories a day for maintenance. Fairly sure the site in question is making the same assumption when issuing its general recommendation.
Let's say Gustavo is average height, and weighs 180 lbs. RMR * Activity Level would put him at 4000 calories. And in the case of serious athletes, this will usually be heavily underestimating caloric needs. It would probably be more perspicacious to break down his activities individually, total them, add in the TEE, and arrive at something like 5000-6000.
Now, if he means he occasionally plays the recreational game of soccer and is otherwise your average gym rat, then you are of course right.
So I suppose what we take from this is we should have first asked for clarification along the lines of, "Gustavo, please tell us what your week's training and activities are. All of it." So, G, it's on you, buddy. ^_^