The more I watch soccer (football for the rest of the world), the less I understand. Which is odd when you consider that, as a Canadian, I’ve had a steady diet of hockey which bears some resemblance to soccer.
For instance, from time to time during a hockey game the puck will end up in the net, having been put there accidentally by a player defending that net. It may go in off of his or her body, or hockey stick. In some cases the player attempts to clear the puck and inadvertently pops it into their own net.
These are clearly accidents, unintentional, not on purpose. Of course the goal counts for the opposing team, and is credited to the last player on that team to touch the puck before it ended up in the net. The player who unfortunately put the puck into his or her own net is not ‘officially’ named. Unlike soccer where the player who accidentally scores an ‘own goal’ is clearly indicated on the score sheet.
This was evident earlier this week In FIFA’s Women’s World Cup 2015 when England’s Laura Bassett popped the ball into her own net while trying to clear it away from the front of the goal. Sadly this happened in the 93rd minute with the score tied. It would hold up and provide Japan with a berth in the final. On the Japan side of the scorecard the goal appears as Bassett 90 +2 (OG). As if she was on the Japanese side and worked at the goal.
That’s just plain cruel! Everyone knows she put the ball in her own net, and those who didn’t see it happen have seen it replayed by now. The whole world is aware of Bassett’s mistake and subsequent anguish. Why rub salt in the wound by naming her?
DCMontreal 
Tradition. They do it that way because that’s the way they do it. If you want a logical reason, sports isn’t where you’ll find it.