>If allowing a particular person to visit means several others will refrain from visiting, is it then a good idea to permit that? That's a value judgement for the organizers to make.

That's part of it, but it's also a value judgment for everyone else to make.

In many cases, the rest of us in society care enough about how those decisions are made that we've passed laws prohibiting businesses from rejecting customers for certain reasons.

For example, if your market research shows that allowing Jews into your event results in lower overall attendance, because too many of the other potential attendees are anti-Semites who refuse to go to an event that allows Jews, you still don't get to ban them. We've established that making those opportunities equally available to all religions, ethnicities, genders, races, etc. is more important than maximizing profit. Even when that discrimination isn't illegal, it's often frowned upon by the culture.

And one reason for that is that we distinguish between the business deciding you can't visit them, and you deciding you can't visit them. We expect businesses to be inclusive, even if that means more people choose to exclude themselves -- because this way, the people who are excluded at least get a choice.

>And if you think they made the wrong decision, feel free to tell them so or even to boycott it yourself, giving them a reason to consider other potential solutions.

I've got no reason to attend a Kubernetes conference anyway, but I have the same interest as any other member of society in ensuring that people get treated fairly.