God destroyed Sodom and Gomorrah because of their evil actions (Genesis 18:16–19:29). With the fuller revelation through Jesus Christ, a town that rejected the disciples' message would receive a more severe judgment.
that town: A whole village or city is responsible when most people reject the message (see Acts 13:45–47, 50–51; 14:1–7). But God will save individuals who trust in him (for example, Lot; see Genesis 19:1–29; 2 Peter 2:6–9).