If hold for themself: Each person makes equal effort
If hold for person behind: Person 1 has to exert extra effort as he/she
has to open AND hold it, while Person Last has to exert zero effort as
the door is already held for them and they don’t have to touch it
If looking at pure equality, the societal standard is arguably less equal.
Well, it basically shows kindness, and society evolved to be like this
anyway…