We know almost nothing about the ancient druids because they didn't write anything down. What little we know was written by the Romans whom they were in conflict with. For example with their claim of human sacrifice on their sacred yew trees it doesn't take into account there are yew trees that bleed blood red sap.

Bash the modern druidism if you want but realise it has no connection to whatever these Celtic people were up to.

It is also umbiquitous to find yew trees in church graveyards here. Is that because they are evil pagan trees that needed cleansing by building a church around them or perhaps they represent something that seemingly lives forever?