it is valid but it is just being used to run them out of business. The actual patent violator is Dorco but they are a foreign company and it would be pointless to sue them. Dollar shave club is merely importing patent infringing razors into the US. But patent law allows you to sue anyone who imports patent infringing materials which makes sense because it can be hard to identify the factory doing the patent infringing but the importer is easy to identify but in this case it is clear who the manufacturer is but it is more useful to sue their competitor than to go after the factory