Corporations that boycott may be in violation of federal laws...
The wording of the legislation you references allows the government from prohibiting participation in boycotts sponsored by foreign states. The excuse that's been used for not prohibiting BDS is that there is no palestinian state, thus they can't prohibit the boycott. Same for the UN blacklist, it's an agency not a state. There's been legislation languishing in Congress to correct that. Personally, I wouldn't mind seeing the administration ban participation and let the courts decide.