Y'all are doing some real mental gymnastics to try justifying this rule. The end zone is definitely considered the field of play. Otherwise you would have defenses standing 50 guys in the end zone.
50 guys in the endzone is too many players on the field. They only allow a maximum of 11 players per team at any given time.
Seriously, though, citing the many differences between the endzones and the 100 yards between them isn't doing "mental gymnastics".. It should be very clear to anyone who watches football that the end zones are treated differently than the 100 yards between them. Obviously there are no touchback rules in the field between the endzones, and calling a touchback on a ball that rolls from the field into the endzone and out of bounds is just one more of the touchback rules. In no part of the field a team gets 2 points when they tackle the ball carrier and make the team kick the ball away no matter what down it is (or should the safety be removed too? Is that rule ridiculous too? ) No one gets 6 points for crossing any other yard line. I can go on and on about the differences between the endzones and the 100 yards between them... but the fact is, the endzone and the 100 yards between them are not equal.
And why do people cite the many differences in rules? Because the main argument against the touchback rule is that fumbles are treated differently when the ball goes out of bounds on the field between the endzones.
And again, the rule book is already heavily tilted in favor of the offense. If the offense is too inept to hold on to the ball before crossing the goal line (which obviously is not like any other line marker on the field) they don't deserve the ball.