This is the most interesting answer. On one hand business is business and if a competitor is truly doing something that is risking the livelihood of it's custom

This is the most interesting answer. On one hand business is business and if a competitor is truly doing something that is risking the livelihood of it's customers, that's not good and they should have a right to know and subscribe to a better service. On the other hand, he is human and might have had a developer that was clueless, etc. His reply would be key to determining which is true. If he purposefully did it to save costs, not caring, etc. then you have good reason to publicly call him out on it. If he truly was clueless and this is a big oh shit moment to him then you have a couple options you didn't otherwise have. If he doesn't have a big dev team (and if he does they seem incompetent) he might be willing to sell instead of spend the money to fix everything. There might also be some other creative solutions that would be beneficial for you rather than attacking it head on publicly.