light IS a EM field. First sentence on wiki: "Light is electromagnetic radiation ..."

And yes, electromagnetic fields interact.

There's a good 2004 documentary by famous film maker John Pilger on the topic of Chagos: "Stealing A Nation".

Fully available on youtube, about 1h long: https://www.youtube.com/watch?v=0zhGvId4fcc

It seems that now also startup companies are (unwillingly, I presume) contributing to this lasting injustice.