If you are downloading and trusting a new software wallet it is essential that you first move your original Bitcoins out of the shared address, in case there is a trojan in the software.
it is not enough to just move your coins out of the "address" specially when you are using an HD wallet such as Electrum. you have to create an entirely new wallet with a new seed and move your bitcoins there and then import the seed into the fork coin's wallet.
you say this later one but there isn't enough emphasis on it, and this is a very important matter people forget.
Actually moving coins to a new wallet would not help so long as you downloaded the Fake wallet and installed in on the same device. The Fake wallet hosted on the website was Malware itself. It would give the hacker a get way to the victims PC and then the attacker would start stealing the coins remotely without the victim's knowledge.
If you check the link to the thread i shared, the victim did not just lose only BTC, he lost even other altcoins