In einer gerechten Gesellschaft spielt es keine Rolle, wen man liebt oder welche Herkunft man hat.

German preposition in is a Wechselpräposition (two‑way preposition). It can take either:

• Accusative = movement into something
• Dative = location in something

Here we talk about a state or condition within a just society, not moving into it, so we use dative:

• in einer gerechten Gesellschaft
  
  • einer = dative feminine of eine
  • gerechten = adjective in dative feminine after an indefinite article

Compare:

• Ich gehe in eine gerechte Gesellschaft. – I go into a just society. (movement → accusative)
• In einer gerechten Gesellschaft ist niemand benachteiligt. – In a just society, nobody is disadvantaged. (location/state → dative)

In „es spielt keine Rolle“, es is an impersonal subject. English would just say “it doesn’t matter”, and German mirrors that with a dummy es.

• spielt es keine Rolle = it plays no role → it doesn’t matter

You cannot normally leave es out:

• ✔ Es spielt keine Rolle.
• ✘ Spielt keine Rolle. – only possible in very casual speech/writing, and then usually with „Das spielt keine Rolle.“

You can also say:

• Das spielt keine Rolle. – That doesn’t matter.

Eine Rolle spielen is an idiomatic expression meaning to be (ir)relevant / to (not) matter.

• eine große Rolle spielen – to be very important
• keine Rolle spielen – to be irrelevant / not to matter

In the sentence:

• spielt es keine Rolle = it doesn’t matter, it’s irrelevant

You could also say:

• Es ist egal, wen man liebt. – It’s all the same / doesn’t matter whom one loves.
• Es ist unwichtig, welche Herkunft man hat. – It’s unimportant what origin one has.

The choice between wer and wen is about case:

• wer = nominative (subject)
• wen = accusative (direct object)

In the clause „wen man liebt“:

• man is the subject (who is doing the loving)
• the person being loved is the object

So German needs accusative → wen.

Compare:

• Wer liebt mich? – Who loves me? (subject → nominative)
• Wen liebst du? – Whom do you love? (object → accusative)

So:
Es spielt keine Rolle, wen man liebt. – It doesn’t matter whom one loves.

Both „wen man liebt“ and „welche Herkunft man hat“ are subordinate clauses (Nebensätze).

In German subordinate clauses, the finite verb goes to the end:

• […,] wen man liebt – liebt at the end
• […,] welche Herkunft man hat – hat at the end

This pattern appears after many conjunctions (dass, weil, wenn, obwohl…) and in indirect questions or clauses introduced by question words like wer, wen, welche…:

• Ich weiß nicht, wen man liebt. – I don’t know whom one loves.
• Er fragt, welche Herkunft sie hat. – He asks what origin she has.

In contrast, in a main clause the verb is in second position:

• Es spielt keine Rolle. – spielt is in position 2.

man is an indefinite pronoun meaning roughly “one / people in general / you (in a generic sense)”.

In „wen man liebt oder welche Herkunft man hat“:

• man means people in general, not a specific person.

Rough equivalents:

• man ≈ “one / people / you”
• du = you (informal, one specific person you are talking to)
• jemand = someone (a particular but unspecified individual)

Examples:

• Man sagt, dass… – People say that… / They say that…
• Du kannst hier parken. – You can park here. (specific “you”)
• Jemand hat geklingelt. – Someone rang the bell.

So the sentence is talking about everyone, not about you personally or one specific “someone”.

Both are possible, but they have slightly different flavours.

• welche Herkunft man hat

  • literally: which origin one has
  • welche is a question word/determiner (like which/what kind of)
  • Herkunft is feminine, so in accusative singular we use welche (not welcher or welches)

• was für eine Herkunft man hat

  • literally: what sort of origin one has
  • a bit more informal / descriptive, similar meaning

In context, „welche Herkunft man hat“ works like an indirect question:

• Es spielt keine Rolle, welche Herkunft man hat
  → It doesn’t matter what origin/background one has.

Herkunft has the following properties:

• Gender: feminine (die Herkunft)
• Case here: accusative singular

Why accusative?
In „welche Herkunft man hat“:

• man = subject (nominative)
• Herkunft = direct object of hat (accusative)

Because Herkunft is feminine, the determiner becomes welche in accusative singular feminine:

• Nominative: welche Herkunft
• Accusative: welche Herkunft – same form (feminine has same ending in nom/acc with welche)

So form doesn’t change here, but grammatically it’s accusative feminine singular.

Yes, that’s perfectly correct, and actually very natural:

• Es spielt in einer gerechten Gesellschaft keine Rolle, wen man liebt oder welche Herkunft man hat.

German main clauses follow verb‑second (V2) word order. You can put different elements into the first position for emphasis, as long as the finite verb stays second:

1. In einer gerechten Gesellschaft spielt es keine Rolle, …
2. Es spielt in einer gerechten Gesellschaft keine Rolle, …
3. Keine Rolle spielt es in einer gerechten Gesellschaft, … (more marked / stylistic)

All are grammatically fine; the choice changes the emphasis slightly.

Because „wen man liebt oder welche Herkunft man hat“ is a subordinate clause (Nebensatz) functioning as the object of „spielt es keine Rolle“.

Rule:
Subordinate clauses in German are separated by commas from the main clause.

Structure:

• Main clause: In einer gerechten Gesellschaft spielt es keine Rolle,
• Subordinate clause: wen man liebt oder welche Herkunft man hat.

The comma marks the boundary between main and subordinate clause.

You can use Konjunktiv II with würde:

• In einer gerechten Gesellschaft würde es keine Rolle spielen, wen man liebt oder welche Herkunft man hat.

Difference in nuance:

• spielt es keine Rolle – present, states a fact or principle
• würde es keine Rolle spielen – hypothetical: in an ideal/imagined just society, it would not matter…

Both are grammatically correct; the original sentence states the principle as a kind of general truth.