Why are my Casual games harder than diamond ranked lobbies ?

@Ryuta47 

Casual games have a less strict matchmaking, regions with more higher ranked players will have the chance increased of matching with them.

So it's because casual isn't really designed for a "fair" match, rather for a "fast" match.

For future posts I'd recommend at least writing a body for your thread, possibly explaining it further in detail and or other cases, title only posts can be resented here and there.