it's really quite simple.
Some knobhead makes it up and posts it on social media.
Then other knobheads believe it because they've just about managed to read it and it makes them feel better about themselves, even though they've had no influence over any of it even if it was true.
Living vicariously by association.
Just ignore the sad ***** marra. Any terrorist supporters turning up with their shit stained barcodes on next weekend will quite rightly take a kicking.