Should sentences using the Impersonal Construction with
se be translated / read as commands? i.e. should
se nada en la piscina y el océano be translated/read as "Swim in the pool and ocean" or "They swim in the pool and ocean?"
That said, the impersonal se construction can be best translated as one does something which, like in English, can be used as a sort of psuedo-imperative in the sense that you're emphasizing that one ought do something in some particular way:
- En mi casa, no se habla de política
One does not talk politics in my house
Obviously, context will be important. The sign a store door that says Se habla español probably means more likely "Spanish is spoken here", although one could equally envision a person in a store yelling at a non-Spanish speaker effectively telling them to speak Spanish by saying Aquí se habla español (which contextually means more likely "One ought to speak Spanish here [and not the other language]")
se can't be translated as a command, but I wouldn't have translated as you did in your example with a "they" (after all, is impersonal).
They swim in the pool and ocean
would be " Ellos nadan en la piscina y en el océano.
Swim in the pool and ocean
Could be read as a command or invitation: "Nada en la piscina o en el océano, donde quieras"; "Nada en la piscina o en el océano, pero no en el río".
Translating the impersonal
se could be tricky regarding the pronoun.
Se hacen trajes; Se hacen arreglos
Could be translated as "We make suits; We fix clothing".
Se duerme de noche y se trabaja de día
Could be translated as "You/We sleep at night and work at day", but definitely I wouldn't have used "They" to convey the generality of the impersonal.