Hi jay81k,
It could be legitimate differences of opinion because there are many things in the industry where you won’t find a consensus of opinion even between knowledgeable and experienced retailers or manufacturers about what is “best” (and it can also depend on individual circumstances as well) or it could just be that a particular retailer is trying to sell you something regardless of whether it may be the most suitable choice or not. The easiest way to tell the difference is to ask them “why” they believe what they do and then you have something that you can “fact check”. You can see an example when it comes to solid surface support systems vs slatted support surfaces in post #10 here.
If your bedframe has good center support to the floor and the gaps between the slats are 3" or less then I agree it would be a suitable choice for an all latex mattress.
Phoenix