I would wager that everyone has said something -- be it in person, over the phone, or digitally via text or social media -- that could be construed as offensive or hurtful to someone, so I get your point, but the facts are that Leipsic is a professional athlete with an elevated platform in a sport that historically has struggled with racism, sexism, etc, and his comments were put on public display for all to see. Regardless of whether or not you feel bad for him that his expectation of privacy was compromised, he chose to say those things (repeatedly, not just once) and he chose to put them in writing, and now that they're out -- regardless of how they got out -- the team and league had to do damage control.
This happens all the time in every walk of life in Corporate America. Execs are unceremoniously let go if comments that paint the company in a bad light are released even if that person worked for the company for 40 years and started as a mail room clerk and worked his way up to CEO. The needs of the many outweigh the needs of the few and if you damage the brand in a way that could ostracize customers, investors, and fellow employees then yeah, your ass is going to be put out on the curb.
Also, for those saying this would never happen if it was Ovi or someone else... no shit. One, they're more important to the success of the business, so the team is more willing to fight the PR fight and two, guys like Ovi who have been around for a long time have become entrenched in the community. They've donated tons of money and time and have created a rapport with the fans and the community. They can withstand a poor judgment in the court of public opinion because they have a lot of goodwill credits in the proverbial bank. Leipsic is a journeyman who is a healthy scratch so he was deemed easily dispensable. If anything, you should be thinking what an idiot this guy is for having those conversations over a traceable medium because he knows he's hanging on by a thread and needs to stay on the straight and narrow in order to hopefully stick in the League.