Everything is used to divide, someone autistic will behave in ways that “other” him regardless of labels, and people who want to hate are going to keep hating.

You don’t need them, don’t use them, but they absolutely are helpful for many people. We are nowhere near a society inclusive enough to make labels obsolete.

Beside, dealing with people’s attitude isn’t the only issue. Neurodivergent people will compare themselves to others on their own, and will struggle with their self image and self-esteem. A diagnosis will help with understanding themselves and finding better strategies much quicker.