Druids are vary depends on the Circle but as is common to see neutral druids of Silvanus is also common to see evil druid of Silvanus as well. It mostly depend on the Circle. Is not like all druid must be neutral. There are also chaotic evil druids the circle of fury druids as well.
Unless they are under the influence of Shadow Druids, which apparently turns them into remorseless child killing extremist xenophobes.