The Encyclopedia Britannica begs to differ.
Roman writers also stated that the Druids offered human sacrifices for those who were gravely sick or in danger of death in battle. Huge wickerwork images were filled with living men and then burned; although the Druids preferred to sacrifice criminals, they would choose innocent victims if necessary.
Caesar is the chief authority, but he may have received some of his facts from the Stoic philosopher Poseidonius, whose account is often confirmed by early medieval Irish sagas. Caesar’s description of the annual assembly of the Druids and their election of an arch-Druid is also confirmed by an Irish saga.
https://www.britannica.com/topic/Druid