I think companies have simply become too weak in terms of their willingness to stand up to protests and letter writing crusades and such. In part because I feel too few are willing to really spend the time defending themselves, or drop the hammer with their rights as property owners when the need arises.
When it comes to something like action figures for "R" rated properties it should be noted that like it or not kids see and get into this kind of stuff. Guys like Freddy Kreuger and Jason Vorhees didn't become icons purely because of an adult audience. As a general rule toy stores have supported themselves by producing toys for a large group of age demographics, and those producing toys have oftentimes put a lot of effort into adapting non-child friendly properties into things more appropriate for children as well. For example "Toxic Crusader" (a very kid unfriendly movie) got it's own Saturday Morning TV show and toy line. We all know about Robocop of course, and when I was little we had things like "Garbage Pail Kids" which were pretty shocking to some adults, seriel killer trading cards, and action figures based around various horror movie franchises of the day.
The way it seems to me is that Breaking Bad is both well known, and responsible in it's labeling, including on that action figure. I don't see a problem with a 15 year old having something like that, assuming the parents think it's okay.
To me it comes down to parenting and knowing your children, and really other parents shouldn't be running around on crusades saying what stores should and should not be allowed to carry for toys and aim at children in cases like this. When a store capitulates it creates more problems down the road by encouraging more people to make similar complaints when they feel uppity, and in the end it lowers their overall stock and reduces the number and type of customers coming in.
Of course it could just be me, my basic opinion here largely comes from some efforts to get "Garbage Pail Kids" pulled, and those cards had pictures of kids with heroin needles hanging out of their arms and all kinds of things as I remember. To me a "Breaking Bad" action figure doesn't strike me as being much worse, especially seeing as it's largely a display piece (dolls like that usually are) and it aimed at teenagers to begin with... and to be honest I don't think kids young enough to be scarred by this are going to really "get" Breaking Bad as a concept to want an action figure to begin with.... and the figure isn't especially exciting or appealing unless you already know specifically what/who it is.
I'd also point out that people need to understand that kids tend to like monsters as much as they can be scared of them. This can create an interesting contradiction at times, but it's pretty normal, and frankly usually doesn't mean that a kid is on his way to becoming a seriel killer or whatever. It's sort of like the old Seriel killer trading cards and such, the point was that they were morbid, not so much that people really wanted to be Ted Bundy or whatever.
Of course then again while this is getting increasingly off topic I suppose the school shootings and the RL attempt to sacrifice someone to Slender Man has generated some paranoia.