The basic point:
1) When you end your union after a labor dispute has arisen, there is still a "labor dispute" for purposes of the Norris-LaGiardia Act; and
2) The NL Act (designed to prevent courts from forcing striking workers back to work) also can be read as prohibiting a court from forcing employers to let workers come back to work.
So there ya go.
One wonders whether the "labor dispute" ever ends. If the players are locked out for, say, 3 years, are they still involved in a labor dispute? If so, wouldn't it be a good idea for all employers to have a union for a few years, then force a dispute, then hire scabs? Right?