Yeah exactly. I hate how somehow, sociologists have recently decided for us that INSTITUTIONALIZED racism is now the only kind of racism. Institutionalized racism/sexism was how this was described when I learned about it.

Yes, institutionalized racism is what does most widespread harm to communities and individuals of oppressed ethnicities and genders. It is terrible and needs to be fought against.

But individuals from any group are capable of assigning attributes to other individuals based solely on their gender or race. Hasn't this, until recently, been sexism and racism?

I think it's very dangerous to wipe out the difference between institutionalized racism/sexism and racism/sexism. A 'racist' incident or comment should not be qualified by the damage it does. If it is assigning attributes based solely on race, it is racist. The damage it does, or does not do, is irrelevant.

Personally I think all racism is damaging, because it is a disordered way of thinking. If a person (whatever their gender/ethnicity) thinks that other people are defined by their gender/ethnicity, it shows internalised, as well as externalised racism/sexism, and can't be good for that individual, let alone the people they are judging. But often, the damage of personal racism/sexism is quite limited. It's when it's widespread/institutionalized that it's significantly damaging to others. Again, this does not mean it's not racism/sexism, just not not institutionalized racism/sexism.

If I, a woman, were to say "All men are assholes", it's a sexist comment

If a man were to say "All men are assholes", it's a sexist comment

If I, a woman, were to say "All women are assholes", it's a sexist comment

If a man were to say "All women are assholes", it's a sexist comment

Because I'm just some anonymous idiot typing on the internet, it does no damage. But it's still fucking sexist. And untrue/impossible.