Realistically that's not true. If you properly do both freshwater and saltwater, saltwater is by far the expensive one and requires a little bit of knowledge to get deeper more into the hobby.Saltwater is no harder than freshwater, especially when dealing with shrimp - you're doing the same water care essentially with RO water and such. The 'hard' part people associate to saltwater is the upfront cost to get a setup going. Nothing different from freshwater shrimp care and saltwater care outside of price at that point (imo)
The care people put in to their shrimp tanks n this forum are above and beyond what many saltwater keepers I known do.