From the Olmec link:
Pre-Olmec cultures had flourished since about 2500 BCE. That's roughly equivalent to the "Pre-Classic" Maya period, which only dates back to 2000 BCE, as per its link. The "Classic" period for both cultures was 1400-400 BCE for the Olmec, and 250-950 CE for the Maya. The Olmec were long gone (650 years!) before the Maya really even got fully into gear. That's likely what the editors of that page were looking at.
IMHO they'd do better to stick to the "Mesoamerican Gulf Coast" language they used later on that page, rather than talk about any specific civilization, since what we should care about here is river valley systems where crop packages were domesticated, but I'm not an editor for that page.
It seems a bit cowardly to leave it at that, so here's what we know about where the Mesoamerican staple crops were first domesticated:
Other important local domesticates:
- Chiles: The Balsas River Valley.
- Cotton*: Tough to tell, but the oldest we know for sure is in the Balsas River Valley.
- Avacado: Independently domesticated 3 times, one of which was in the Balsas River Valley.
(The earliest evidence we have of the domestication of the Tomato also comes from southern Mexico, but its wild ancestor is native to Peru and Equador, so it was certianly first domesticated there.)
For fun, I've helpfully circled these river valleys on a detail map of Mexican river systems:
* - Varieties of Cotton were domesticated independently all over the world (because its a damn useful plant). However, the most commercially useful variety, the one most everyone today uses, originated here in Mesoamerica.