importance of PCB/Trace antenna position relative to components
Well, the antenna contacts are on the top of the module under the metal cap  – you'd have to build an RF transmission line (for example, a coax cable, or a microtrip line) to attach any antenna at any other point than that. 

Since that is relatively complicated and hence relatively expensive, these modules where designed and tested to work with the antenna in that position – and this specific antenna has been designed to work in that position. 

Especially, the antenna seen relies on a ground plane south of it – so, it's not an antenna that you could just use anywhere. You'll need a different antenna type if you want to put it elsewhere, where there's not nothing north, and not ground plane south of it.

If you don't want to use that antenna, you can simply not buy a module with an integrated antenna. But: you'd then have to do the RF design yourself, and bad news is that at your current level of experience, this won't lead to satisfactory results.