Tokolosh,
You make some valuable additions to this conversation. You raise some good points about other legitimate impediments that people have to bike commuting. There was a thread in the past couple of weeks over on the "Living Car Free" forum that raised similar questions about how realistic it is to do without a car with kids. Personally, I think parents with young kids have to make very different commuting decisions than non-parents.
Normally my wife takes care of dropping off and picking up our son from school, but when she is travelling on business or gets held up at work I have to cover it. I enjoy riding with my son to school and it is very convenient for us (not true for everyone), but trying to get to his school before after school care closes can pose a real challenge. Fortunately, if I plan ahead I can shorten my commute and catch the subway in. That makes it a little easier to meet the schedule.
Rather than an "all or nothing" approach that die hard bike commuters sometimes preach I'd rather see us encourage newbies to ride at least some of the time. If would-be bike commuters rode even a few days a week they would lessen traffic and enjoy the benefits of more exercise. For the biking community, the upside would be more advocates out there to support biking facilities and bike friendly planning. For instance, here in DC we have a reasonably good bike infrastructure, but you can't bring a bike on the subway during rush hour. While there are good reasons for the rule it severely limits would-be bike commuters who may not have time to do the full ride, but could do part of it. More bike converts could mean more people to push for more bike friendly policies on the subway.
We shouldn't let bike commuting become a dogmatic test.