We discriminate on those things during hiring because all of them are directly relevant to the job. If you have a social job, you need good social skills. If you work with other people, then someone who makes the people around them or certain groups of people they work with/could potentially work with feel unsafe shouldn't be there. If you have to use a certain technology to do your job, and there is no reasonable workaround for that, then they aren't suitable for the job.
Discriminating on literally ANYTHING else, on ANYTHING that is not relevant to the job being done, is blatantly awful and should not be promoted on any level of any organization. This shouldn't even be a controversial issue.
>this is not an argument for hiring people who are "just like me", or an embracing of the status quo. This is an argument for exercising judgement on specific topics which should be universal in a civilized culture.
What those specific topics are, or what you think should be "universal in a civilized culture", is completely up to each person. That's pretty much what political opinions are. And this type of thinking is the basis of a lot of discrimination that we should not be promoting in absolutely any way. If someone had a religion that promoted war , would you not hire them? What about if someone is from the south, and you haven't heard them be racist but you know how those southerners are. Is the law literally the only thing that's preventing you from saying no to these questions? If the answer to any of these are yes, then you are contributing to discrimination that has absolutely no place in the world.