People can be so rude?

I remember when I had a miscarriage, I had to see my doctor and the only way to get there at the time was by train, now the train was packed full but someone was kind enough to offer my mum their seat, she gave it to me because she knew about my condition, this sparked a large debate among the other pengers about how rude and selfish I was and how I was robbing seats from people who really needed them. so my question is, if you saw someone offer their seat to someone and they promptly gave it to someone else, would you think that person was rude or selfish?