Samsung does it too here is a excerptI think they just don't care about OnePlus (market share <1% in the EU I guess).
Imagine punishment up to 10% of global turnover of Apple !!! LOL
"Apply to WPC certification program including Samsung PPDE(Proprietary Power Delivery Extension) safety compliance test and check if the wireless charger is fully compliant to Samsung Fast Charge specification"
right from their webpage
Edit: Adding...therefore if you do not meet/apply for for both the cert, but more importantly their PPDE you will not have Fast Charge.