Sounds like operator error to me. Be sure you are using the tool correctly.
The pin that you are pushing out has to be completely within the slot in the bottom of the tool so that it can freely come out. If the pin is hung up anywhere on the body of the tool, it will not come out and the handle will be almost impossible to turn, which sounds like the problem you are having.
Any chain I have taken apart with my cheapo tool came apart very easily when properly aligned in the tool.
Il faut de l'audace, encore de l'audace, toujours de l'audace
1980 3Rensho-- 1975 Raleigh Sprite 3spd
1990s Raleigh M20 MTB--2007 Windsor Hour (track)
1988 Ducati 750 F1