I agree with Matt here. They are employees - even though there is a contract the fact that this string exists because baseball is pushing the Feds to codify the exemption tells me enough to believe that THEY think these guys are employees and they want a law to say they are not.
The guys that own MLB are not inclined to take unnecessary chances on this front. They want the Feds to shield them from paying their labor like any other employer.
In the crassest way - politicians are taking the campaign money from this special interest precisely because there will be no backlash that baseball players will protest or get any widespread public support.
Do the same thing for McDonald's or Walmart and there is a shitstorm of protest and probably charges of racism and misogyny as cherries on top. Not a politician in the land will go there. But screw a couple of thousand kids playing baseball - a bunch of whom aren't citizens that can vote while picking up campaign loot. JACKPOT!
I call BS today and twice on Sunday.