Personally, I'm cool with it. I have a couple friends who racewalk and I'm as glad to see them succeed in their sport as I am when my running friends succeed in theirs.
You'll never get 100% agreement when it comes to sports. Look at what happens when someone posts about triathletes (and you'll see anti-triathlete threads not only on running but also swimming and cycling forums).
Myself, I'm not that keen on watching, let's say, weight lifting, but I won't say no one should pursue it as a sport or it shouldn't be taken seriously. Just not something I'd get into watching.
In swimming, there's competition in different types of strokes, so I don't see why, in track and field, there shouldn't be competition in walking as well as running.
I actually tried a racewalk event... and it offers its own kind of challenge: resisting the temptation to run while walking as fast as possible--and working different muscles. I wasn't converted to racewalking, but I was glad to have the chance to try it--and if my running injuries catch up too much, it's good to have a back-up plan.
Running has its share of detractors too -- naturally they're wrong ;) -- but I guess those rivalries will persist no matter. Let them talk... while you racewalk. (Pardon the rhyme... or not.)