Obviously the legs getting caught in a child's' mouth is a very real risk, and it helps to be aware of this if you plan to buy a Sophie but I don't think it's a reason to boycott the toy altogether. If we took that stance with every toy that posed such a risk then our children would have nothing to play with at all.
I think it's worth remembering that a lot of these incidents could be due to unofficial Sophies - there are lot of replica versions out there which, on first sight, look like the real thing. And if you think about it, a lot of people buy Sophie as a new baby gift so the parents won't actually realise that it's not an official product if it isn't. I know that at least one of the choking incidents reported on Facebook was due to an unofficial Sophie. I'm not saying that the toy is definitely safe, but it has to have been safety tested and the fake ones probably haven't been.