Because it's the right thing to do. There's a difference between technically being responsible and what is ethically and morally correct. The line situation is beyond insane now according to this thread. People are lining up, and whether they are encouraging it or not it doesn't matter. It's happening at their door step, continues to get worse, and in my opinion they need to take action. Hopeful they'll have an online system soon and the line will be history. Hermes is an iconic luxury brand, with that status, they should own up the the responsibility to ensure a safe and pleasant environment while shopping for their brand.
But they also want to earn a lot so therein lies the dilemma. H is one of the few luxury brands not affected by economic slumps and downturns, and I think most of it has to do with them being aggressive with selling and their prices. So, as long as no one has been injured yet because of falling in line, they will take their sweet time to fix it. Why should they, when the store is earning so much. Their allegiance lies to their company and employees, not to customers who (mostly) only want a birkin or kelly.
You should visit FSH if you haven't. It's so surreal. A store selling keychains as expensive a month's wage of an employee in a developing country, and yet it feels like a fish market inside with all the noise and people.