"I wish creatures wouldn't be so easily offended!" is a phrase expressing frustration with the quick sensitivity of others. It hints at a desire for more patience and understanding in interactions. The speaker wishes for a more tolerant attitude in creatures who often take offense too easily.
"You'll get used to it in time," said the Caterpillar, and it put the hookah into its mouth and began smoking again. The Caterpillar's words suggest that with time, one can become more accustomed to such sensitivities, implying patience and experience are key to dealing with easily offended beings.