That’s only true for punts. Kicks are live balls and can be caught or recovered by either team, even in the endzone.
Here’s how I view it.
First, the second and fumble happens neither team has possession which is indicated by the ref tossing his bag.
The offense has 100 yards (from goal line to goal line) where if the fumble goes out of bounds, then they are awarded possession at that spot even when they didn’t recover the ball. (Unless its 4th down, then the ball goes back to the spot of the fumble).
The defense gets the endzones. At one end they get a safety and the ball after a free kick. At the other end, it’s a touchback.
Seems fair to me. Offense gets 100 yards for automatic fumble possessions, defense gets the endzones.
If they were to ever change the rule, then I don’t think the offense should be given the ball at the spot of the fumble. The only change I would be happy with is that it is still a touchback but, the offense gets it on the 25 instead of the defense. This way the defense is still rewarded for causing a fumble near the endzone but, the offense doesn’t automatically lose possession.
In the end I like how it is now though. Defense gets the endzones, offense gets between the goal lines.