UFC is only allowing COVID vaccinated into their event in Jacksonville.  Is this discrimination against anti-vaxxers?

Yes it's a decision a business can make like no shirt no shoes no service. The bad thing is UFC does not realize the vaccine is not 100% even if someone doesn't get the vaccine because they're immunized they can pass it to somebody else and there's a mutant strain of the virus

No, it's a reasonable precaution to protect people at the event.

No, it's called "actions having consequences."  You made the decision not to get vaccinated.  UCF made a business decision that they did not want unvaccinated people possibly turning their event into a superspreader event.

They are a privately owned concern, and have every right to set the conditions of admission.

I don't know if it will come to this as far as transportation like the airlines, the railways or Greyhound, but it's the same deal.  They are private corporations, and if they decide that it's best for their business to require the vaccine in order to travel with them, it is their right.

No, just like it's not discrimination when the cops pull someone over for driving down the wrong side of the road. It puts other people in danger. 

Yes, it's discrimination.  Anytime you make a decision, you're discriminating between the options.  The question is whether it's illegal or unethical.  It's clearly not illegal.  I don't think it's unethical either.