It's not specializing when you play a bunch of things, that's the opposite of specializing.
Also:
During the 1992 season, his best year in the majors, Sanders hit .304 for the team, stole 26 bases, and led the NL with 14 triples in 97 games. During the 1989 season, he hit a major league home run and scored a touchdown in the NFL in the same week, becoming the only player ever to do so. Sanders is also the only man to play in both a Super Bowl and a World Series. In four games of the 1992 World Series, Sanders batted .533 with 4 runs, 8 hits, 2 doubles, and 1 RBI while playing with a broken bone in his foot.
Bo Jackson competed as a sprinter, hurdler, jumper, thrower and decathlete in College.
You can specialize and play a bunch of things. Pretty much everyone does it. You can be a chess prodigy and still play checkers, monopoly, video games, etc. Using your logic, nobody specializes because they all do other things.
As for Sanders, I'm well aware of his football and baseball careers because I was a kid who grew up watching him in the 90s. 1 "decent" season doesn't make a "phenom". Okay? In 1992, sanders didn't make the all-star team, he didn't get over 100 hits, he played less than 100 games. Sanders career batting average is the .260s. He was nothing special in baseball. Unless your definition of "phenomenal" is different than mine. Deion Sanders was phenomenal in football. He is arguably the greater cornerback in NFL history and a hall of famer. If deion sanders was a phenomenal center fielder, then what is ken griffey, kirby puckett, etc?
As for bo jackson, how about he specialized in track&field, baseball and football. You can argue all you want, bo jackson specialized. He didn't go into curling, badminton, tennis, hockey, etc. He didn't "generalize". He was a rare phenomenal athlete who could specialize in multiple sports.
If you disagree then your definition of phenomenal and specializing is different and we are simply never going to agree and I'll just leave it at that.
Also: During the 1992 season, his best year in the majors, Sanders hit .304 for the team, stole 26 bases, and led the NL with 14 triples in 97 games. During the 1989 season, he hit a major league home run and scored a touchdown in the NFL in the same week, becoming the only player ever to do so. Sanders is also the only man to play in both a Super Bowl and a World Series. In four games of the 1992 World Series, Sanders batted .533 with 4 runs, 8 hits, 2 doubles, and 1 RBI while playing with a broken bone in his foot.
Bo Jackson competed as a sprinter, hurdler, jumper, thrower and decathlete in College.