I bet they don’t actually guarantee it, though many rely on that! The package actually says it is safe for latex only – as you know chemical compatibility is dramatically different depending on rubber polymer backbone and the anti-degredant and compatibility packages in the mix. Natural latex is so sensitive to so many things though that I would be surprised that anything compatible with it would be incompatible with the synthetic rubbers. Some of KY’s more sophisticated lubricants, I was surprised to learn, are not compatible with any rubbers. I don’t have to care but I suspect that has surprised some other folks as well! It actually must be kind of a fascinating business to design those lubricants - rate dependent shear thinning fluids.
Is it from the Book that I learned that one of the challenges with British rubber products is that there was some incentive or requirement to use some percent of natural latex rubber (from Britain’s many colonies) in British rubber goods to subsidize/stabilize that industry when the synthetics were really taking over the market and that compromised the performance of many British rubber goods? I used to work adjacent to the elastomer industry and may have picked that up somewhere else.
Regardless, I always like to check out Parker Hannifin’s chemical compatibility guide whenever using a chemical around rubber of any sort. Easily available on the web. Bringing it back around, while I always use water based lube like KY for EPDM, be careful to not grab the silicone based version and use it on silicone hises! Very ungood.