There are two major forks of Bitcoin, one of which is legit and one of which is basically a scam.
Bitcoin Cash is the first and forked in mid-October.
Bitcoin Gold is the second and forked... at some point. It's not actually hugely clear.
Anyways, Electron Gold is a fork of Electrum, which is a lightweight Bitcoin wallet. The idea is that you would load your Bitcoin private keys into Electron Gold to "split" your Bitcoin and Bitcoin Gold, and gain access to both.
However, it looks like
Electron Gold also sends your private keys to a third party, allowing them to steal both your BTC and BTG.
https://www.reddit.com/r/btc/comments/7eve94/confirmed_electron_gold_steals_private_keys/Where did you get that Electrum Gold is a fork of Electrum?
Electrum Gold is closed-source and doesn't have any git repository.
They are not connected to Electrum in any way.
Seems they mixed a wallet with a fork
So, they are warning against Electron Gold wallet, for keeping Bitcoin Gold crypto. - this is what I understood.
In fact , BTG turned out to be a token, with al lot of scams are around. Fake emails from Blockchain.info arrive in big qty, also proposing to claim BTG, by disclosing private keys.