Discrimination just means "making a choice" and it's not a bad thing. The problem is "unfair discrimination", where you take factors into consideration that are

Discrimination just means "making a choice" and it's not a bad thing. The problem is "unfair discrimination", where you take factors into consideration that aren't relevant. If you were to ban all discrimination, then you couldn't choose who you hire for a job - after all, you couldn't discriminate against people without relevant experience, or skills, or abilities, could you? Relevant discrimination is not only okay, it's essential! So the problem then becomes trying to define laws in such a way as to disallow the unfair discrimination while also allowing reasonable discrimination. People who are determined to be, eg, racist or homophobic will try and use the very edges of the anti-unfair-discrimination laws to get away with unfair discrimination that is obviously unfair but _technically legal_. And that's how you end up with complex laws and lists of protected characteristics.