Is it just me or are men less empathetic to pregnant women on the trains? So far only women have given up their seats to me.

On the contrary, men have always given up their seats to me. I've had some extremely rude reactions from women. I was lucky in the sense that I never had to stand. On days where I wasn't offered a seat, I would just blatantly ask for the priority seat. Rather than keeping quiet and lament about how nobody is giving up the seats, just ask for a seat. If you genuinely need it, people will vacate the seats for you.