I get where you are coming from Rene.
You were probably hoping for something like this
L.esri.featureLayer(featureLayer, {
spatialMethod: 'intersects',
geometry: latlng
}).addTo(map);
Implementing this would be VERY difficult since the assumption that features are only loaded inside the current viewport is baked into Esri Leaflet all the way down to the core.
That said this did remind me of a feature I wanted to add Add additional spatial query types to L.esri.Tasks.Query · Issue #374 · Esri/esri-leaflet · GitHub.
Once this is implemented you could do something like the following to render all polygons that intersect a point.
L.esri.Tasks.query(featureLayer).intersects(latlng).run(function(error, geojson){
// use L.GeoJSON to add features to map
});
For right now you can just use the raw L.esri.Tasks.query to query as many features as possible and use Turf on the client side for your point in polygon.
// queries all features up to the transfer limit (usually 1000-2000)
L.esri.Tasks.query(featureLayer).run(function(error, geojson){
// now use Turf over all the geojson
});