Depends on how you define “MO”
if you think of nominally affiliated, marginally observant Yidden, they are not “MO”, but of course should be helped
If you think of people who go to YU and maybe go to court without a kippah after attending selichos in the morning – they may not benefit from your help, as they might be more learned than you are
If you think about people with crazy modern fetishes, like OO – they might be not receptive to your preaching. You may want to take a sefer, not directly addressing their fetishes, and sit and learn with them. At some point, with more learning, they may get better