This thread very much seems to assume that our grandchildren will simply be more extreme on what are currently slight fringe issues- e.g. vegetarianism will eventually convert everyone etc.
What our generation thinks is fine, previous thought was immoral and vice versa. I have no idea what that will be, but our grandchildren will probably support some truly horrible stuff (to us).
Additionally, we'll probably all be known as monsters for something we find trivial- best guess is eating meat, but maybe we'll get condemned for not taking up cryogenics quicker and saving some lives. Who knows?