Literally: a server should be free to decline services to specific clients - service is conditional. It should be easy for anyone in general to think of a list of clients one would not work for.

Contextually: the point is more like "we do not accept that these springs we build can be used in landmines". It ecompasses the literal point, yet it is different - at least, it refuses the purpose, not the person.

That's not quite the same thing. Can a server or some other service provider refuse for any reason they like? What about protected classes? Should there be a whitelist of "good reasons"?

Purpose and person are hard to separate too. Like if you will sell cakes to anyone, except that nobody will be given a cake if it's for a gay wedding.