The hardest part of seeing snakes in these conditions is not buying them. I remember back when I owned iguanas I went into a local pet shop in the mall, and their reptile conditions were atrocious. Looking back, they were all in pretty bad shape, but I only knew about iguanas at the time. The poor babies were caked in their own poop, each one had at least 3 different burns, and not a single one had all of its toes still intact. It probably didn't help that there were about seven of them in a tank roughly the size of a ten gallon, with the light in the tank. There were also crickets all over the cage, and I cringe every time I hear of people offering an iguana crickets.
Of course younger me wanted to take them home and get them healthy, but if I had tried, more mistreated babies would have came in to take their place. The best you can do is let the store manager know "I came here to look at these lizards and supplies for my colleection, but seeing the condition they're in, I won't be purchasing anything from this store." Taking them home doesn't work, neither does telling the associates they're going to kill the animals. Telling them that they've missed out on a sale and lost business, plus the threat of telling the other local reptile keepers to not give their business either, now that's effective. As someone already mentioned, they're out to collect a paycheck. Threaten the check, see some results.