“and rashi there even says that the posuk is refering to going to theaters like the goyim and places of sports and the likes.”
“Going to the Theater is Assur ONLY because its IN PUBLIC”
If that were the way we paskin today, we would have to ban many Jewish frum concerts and events which are held in theaters and sporting arenas; i.e., siyum hashas, chazanus concerts, YBC, MBC, graduation ceremonies, etc.