What's been attempted to point out is that the 'strong evidence' was for only for that the flagged moved. It is jumping to conclusions to assume the cause. One can't conclude it is proof of spiritual beings, and then further conclude that means there is a god and creator. What makes an assumed 'unseen being' also a proof of a god? That isn't just one jump to a conclusion, it is multiple.
One could also jump to these conclusions...
- the phenomenon was advanced alien life playing along and moving the flag for shits and giggles
- it was contact with a parallel universe in which another version of yourself moved the flag
Those are imaginative speculations of the cause, but that is all they are. Concluding spiritual beings and then connecting said beings to a god is simply another imaginative speculation.
Personally I like the parallel universe/version of yourself one...that's much more fun.