That is incorrect. You do not need to move your coins out of counterwallet. Your BTC is perfectly fine/safe in Counterwallet during the fork. When the fork happens, if you had 100 BTC in your address, you will still have 100 BTC in your address… nothing changes.
Now, if you want to actually split your coins into BTC and BCC, you can do so OUTSIDE of the counterwallet system. All that you will need from Counterwallet is the private keys for your address.
Once the split happens, there will be BCC websites/tools that will appear to allow you to “split” BTC/BCC coins by simply pasting your private key into a website/tool.
All that a “splitting” tool allows you to do is move your BTC and BCC independently of one another. If you only care about BTC, you don’t need to do anything.
If you want to get your free BCC, you will need to wait until the fork, then get your private key from counterwallet, then paste it into a trusted “splitting” website/tool.
TL;DR… your BTC coins are 100% safe, and if you want to split to BCC, your able to using your private key.