Though some are often inauthentic and doing it to try to gain favor, many don’t recognize that the chameleon effect can happen quickly, even with strangers. Mimicking speech patterns can be very subconscious. Also, studies have shown a connection between empathy and adopting speech patterns/accents.
People are making fun of AOC for having a slight southern accent while speaking in Memphis but they clearly don’t know the pain of habitually and unconsciously imitating the speaking style of the people around you