So by your logic, only comp riders are trials riders, the rest of us are just guys with weird bikes.
That makes virtually none of us on this forum trials riders.
Unfortunately it depends on your definition of the sport.
Football, is a team sport where people form teams and attempt to score by putting the ball in the other team's net.
Trials is riding a bike over obstacles.
So no, a kid kicking a ball against a wall isn't football, but anyone who rides their bike over something is technically doing trials, just like when you and your mates do 3 a side kicking a ball between piles of jackets it's technically football.