The warning is valid for electron cash.  Talk about a way to gather private keys then sweep everything at a laster date

Those brave enough to use electron cash I just did it

To make sure that your private Bitcoin key doesn't stay compromised, move your Bitcoin to a different wallet that is temporary and you will not use again.  

Get your 12 word backup master seed from the new wallet that you should have written down

Install electron cash on a computer or device that DOESN'T HAVE ELECTRUM WALLET

Select that you already have a master seed or private key

Type the 12 words with spaces between the words ie "mister kilo missing you like loco loco Moco love mitagate oil pilot"

You'll notice the next box is greyed out

Click options and select the BIP138 box

Click next and bingo you'll see your Bitcoin cash balance

Now the MOST IMPORTANT PART.  Empty your new Bitcoin wallet. Delete it and even better format the computer you used
Empty your electron cash wallet to an exchange that supports Bitcoin cash

Cash it in or trade with it