Yea, it takes some force to lock the ratchet on that side with the plastic. You really don't have to use that plastic if you don't want to. Its purpose is to spring your ankle strap out of the way when you unstrap so it's not in the way when you are stepping in to strap in. Some people don't like this feature and cut off that plastic.
I really like the feature. You can make it tighter to make it spring further out of the way. Once you lock it, it will be easier to unlock/lock from there on.
I didn't have much problem locking it the first time, but I guess others do. Makes me feel strong