No, they are not inherently bad. It is all about moderation; eating fast food a few times in your life won't kill you, and if you are disciplined you can still make some healthy-ish choices at fast food restaurants.
If fast food restaurants are banned, what is the stopping point? Will we have to ban bars also? Their food is not particularly healthy and alcohol has little nutritional value. Will bakeries have to be eliminated because they do not serve nutritious fare? And what about the higher end food restaurants that do not serve particularly healthy food-- should they be closed down? (And if not, that seems to reek of some kind of economic discrimination.) Where is the line drawn and who is drawing it? Why should someone even get to choose what other people should or should not eat? Just because some people gorge themselves on unhealthy food does not mean no one should be able to have it.
And if our goal is to have everyone be healthy, how healthy should that be? If it were up to a health nut like my dad, people may not even be able to eat whole eggs or cheese because of the fat content. If a vegan was deciding, then perhaps meat would be deemed unhealthy. Fresh food proponents might ban all frozen meals, even the more nutritious ones, because they think preservatives are unhealthy. "Healthy food" is entirely too subjective to use as a basis for banning.
Painting certain foods as evil doesn't address the real problem-- that people do not know how to eat healthfully or merely do not have the self-control to eat healthfully. We need to teach people to improve their eating habits so they can coexist with McDonald's yet still have the discipline to stay healthy.