So, if women can have the option not to ride with men, which is no problem. Then why can't men have the option too?lWhat harm does it do to women if men can have the option as well?

There is no good way for me to interpret this, it must be an ulterior motive in there.

Either 1: the person saying that is a misandrist that, although they did have negative experiences with men, this does not justify their contemptfull attitude towards men, which they cover up under the excuse of protecting women.

2: They actually believe their gender should be have advantages. That just because they were born a certain gender, that gender should have advantages. Like, finding excuses for why the other gender deserves less.

3: They are afraid that giving men an equal option will make them seem like an Incel that is trying to make it seem like men are equally vulnerable for propaganda reasons, so they are afraid to choose the just and equal option, just because they are afraid of backlash. So men get dicked over for little good reason, because westerners see everything as zero-sum.