One, we have to be careful with generalizations. Two, what kind of empathy are we discussing here,...cognitive and/or emotional?
Many autistics are often quite good at emotional empathy,...will cry and laugh when it is appropriate, tears on the cheeks watching a sad movie scene,...whatever. However, perspective taking is often a mental exercise,...it is an active process that requires some degree of willingness or openness to it. In other words, even IF you have the mental wiring to have cognitive empathy,...it still requires some mental energy to really embrace another's perspective.
You see examples of this frequently in the people around you,...one moment they are loving, thoughtful, and caring,...and the next moment they are perhaps throwing around impulsive racial slurs, yelling expletives at someone, just being nasty towards another person or group. The later being emotional, impulsive thought patterns that completely bypass those logic centers responsible for perspective and cognitive empathy.
Not all autistics are lacking in cognitive empathy,...that is a generalization based upon studying mostly children and coming up with statistical analysis,...and even those that have difficulty with it, still can have it IF they pause and be thoughtful enough to ask the appropriate questions in order to understand another's perspective. As an adult, I am much better with these things than I was in my youth. However, I still have ZERO idea what my wife is thinking after some 37 years with her,...I don't get her hints,...I never have,...I have to be thoughtful enough to pause and ask.
But, more to the heart of your concerns,...the short answer is that many people embrace sameness and conversely, do not like differences,...especially in people around them,...this seemingly instinctual thing we call "tribalism". Whether it is your racial, religious, or political identity,...you tend to be attracted to what is similar to you. When it comes to behavioral things,...again,...if you act different, you're not welcome in the group,...part of the reason so many autistics have difficulties with socialization. Neurotypicals see something, however subtle it may be in our behavior,...and they back off. Many of us suffer from not being able to maintain a friendship,...part of it is us,...but part of it is also the other person not wanting to bond with someone who is "different". Because these innate feelings are being filtered through the amygdala, and not the logic centers, cognitive empathy is also bypassed. Hence, the issue in which you discussed above. This affects our ability to maintain employment, have successful marriages, find friends, our propensity for depression and suicide,...the list goes on and on.