I don't see conflating racism, sexism and ageism very useful. They all have different causes and validity, depending on context. Does attaching -ism after the word "nerd" make nerds suddenly an oppressed group?

There's nothing wrong with discrimination as such. Dividing two things into separate compartments gives us the ability to process their differences instead of trying to fit two thing together that do not go together, again, depending on context. But discrimination definitely is a very useful mental tool.

A word about racism. I see it mostly as an in-built defense tactic for territory and one's own genetic line. Is this outdated? Perhaps. Does this have anything to do with sexism? Not really that I can see. Other than the -ism at the end.