I'm not going to let someone tell me with a straight face that POC and women wouldn't attend a job fair unless it explicitly banned certain demographics from attending. It's wishful thinking. If the league has such a strong "whites only" image then how could there be such a large, disenfranchised non-white fan base and potential applicant pool in the first place?
Even still, it's common practice to include in job postings themselves notes saying that applications from certain marginalized groups are encouraged. The same logic would hold that marginalized people would not apply for a job unless it explicitly said they would only consider applications from that group. You will lose all credibility if you try to argue this is also common.
The NHL knows it's own reputation and likely has the data to support it which is why they are on a push for DEI. Certain demographics (mainly African-Americans) would probably not even consider an NHL job fair or job listing based on the perception that a White organization would not hire them. A job fair that sounds like the league is open to hiring persons of color is a different story because people of color would attend if they felt as if they had a fair chance. Companies find talent by casting a wider net.
It's not a guarantee but it's daft and strains credulity to argue that there is no connection between job fairs and guarantee of employment. Under your logic it's just as justifiable for the NHL to have a whites-only job fair because "a job fair is not a guarantee of employment".
I didn't say there was not connection, just that there is no guarantee of employment. One still has to have the proper qualifications to get a job. You have no legal argument that anyone's civil rights were violated or even at risk of being violated. The job fair never happened anyway.