I don't understand your objection. It is an amazingly simple tool for collaborative editing and I don't know of any free software alternatives that are as easily usable.
If someone's on a diet and refuses to eat chocolate because that would be against the point of the diet, countering with "I think you should try it---it tastes so good" completely misses the point.
I know Stallman isn't interested in products because they're "better". But he should be - even if only to push the free software movement to make itself even better.