EU requires all EVs to use the Type 2 CCS charger so Tesla was compelled by law to create the CCS adapter. What was the reason for the Chademo adapter
No, the EU does not require EVs to use Type 2 CCS. (For example the Leaf, and other cars, uses CHAdeMO. Others don't even support DC fast charging at all.) What they require is that public DC fast charging stations have Type 2 CCS connectors available.