They are also very "natural" spells, utilizing sunlight, and druids represent nature and life, which is more or less the opposite of unlife. To my knowledge, there are quite a few druid orders who seek to destroy undead in Forgotten Realms and other settings.
As for my point, I was mostly referring to the Heal and "Healing Circle spells, which the clerics get one spell slot earlier than druids do. Clerics also get Mass Negative Energy Protection and Mass Death ward a level earlier than druids, for example. As for druids, they get spells such as "Regeneration" and its variants a level early, as well as offensive spells such as Fire Storm and Ice Flowers. Clerics also have access to defensive spells that druids don't have access to, such as Magic Vestment and Aura Against Alignment, while druids have access to offensive spells that are not available to clerics, such as Deadly Lahar and Finger of Death, and some unique offensive spells as well, such as Call lightning and Sunbeam. It of course doesn't apply to all situations, for example the druids have access to Barkskin spell, which is a defensive spell unique to them and ranger class, but in general, druids have a spell list more focused on regeneration, debuffs and dealing, often elemental, spell damage while clerics are more focused on regular healing, buffing themselves and buffing others.