Honestly mostly with common sense.
I explain the tag has no power or battery and gets energy from the thing scanning it.
I explain how it works and it contains off the shelf electronics (NTAG chip) designed for use in a clear glass package.
No GPS tech is small enough to be implantable and would be impossible due to the lack of power source.
Mark of the beast is a hard one as its religion, its up to the person if they decide its the mark or not.
I’ve been asked if it gives me aside effects, I explain what it is and that its just in biosafe glass, I normally have the xLED on me just to show people the size and rough design.
If they don’t want to listen rather than wasting time arguing, state these things and then walk away if it gets heated. Its not worth the energy and sometimes for now there isn’t changing peoples minds. Over time this will become more common and acceptable.