If penalties were truly random then teams wouldn't practice them. Goalkeepers wouldn't study their opponents' past penalties or use cheatsheets when facing kicks. There wouldn't be so much analysis and game theory poured into the perfect sequencing of kick-takers.
It's true that penalties test fewer skills than a full-fledged game of football. But they are still a contest of skill, not a game of chance.
People are not robots. Penalties do test the nerves of both teams. And besides, the feeling of fairness is more important than actual fairness in football. We don't watch it to get a perfectly stat driven understanding of the game, but because it's fun and emotional.
Penalties are not random at all. There is a reason why some teams suck big time on penalties while others nail them all the time (or almost always, depending on the generation, players, etc).
I meant "random" is a sense that it doesn't really reflect which team is the best in the world. Penalties is a player-specific skill, but the football is a team sport first and foremost and the world champion status should reflect that.
If all that matters is to recognize the best team, then why bother with a knockoit stage, or even a world cup tournament? Just collate stats. The point is to play the game, and if both teams are evenly matched in regular play, to move to an acceptable tiebreaker so that someone wins. France has still come a very close 2nd place, which the tournament does reflect.
Penalties is just a more elaborate form of a coin flip, still largely random.