Summary in no particular order:

1. DC is a commuter city, with many non-residents coming in and out daily. This means less behavior ownership.
2. DC has some complex intersections and bike lanes, with formats/rules that MD/VA drivers aren’t used to potentially.
3. Covid reduced driving practice and increased the feeling that ordinary rules were no longer in place/needed.
4. Society certainly seems less nice over the last few years, whether because social media has turned it into the Roman coliseum or leaders that engender that kind of attitude.
5. Phones.
6. DC has always been a tough pedestrian navigation regardless.