Even if your Electrum is genuine, if your OS is compromised then it's game over. So these measures can help you control the software running on your computer.
is it unsafe if I used Windows 7?
Windows 7 supported newer versions of Electrum, then my answer would've been: only if you use it as an offline, airgapped (never connected to the internet) wallet.
However, now that Electrum does not support Windows 7, you should not be using this operating system to store you wallet as there may be unpatched security vulnerabilities inside old versions of Electrum in the future.