The problem is not with desktop wallets, the problem is with your environment. For example if you are using windows and connect to the internet with it, there is a good chance that it gets infected with some sort of malware/keylogger and when you use a bitcoin wallet you can lose your funds (among other risks).
I think that's a bit too strong of a statement to make. It's not like Windows is searching for keyloggers and dangerous malware it can infect your machine with. You are right that it's about the environment in the sense that +90% of viruses and malware are created to target Windows users simply because there are so many of them and the OS is easier to work with compared to popular Linux distros. Hence, it's more popular among newbies and security-unconscious individuals. But if the users stay away from unknown sites, services, files, etc. and stop believing that the rest of the world is there to help them get rich, they will avoid malware and keyloggers.
Bears don't attack joggers wearing Adidas gear more than they attack those wearing Nike. They attack those who came to close, surprised them, scared them, or to protect their younglings.
I was just wondering if electrum was a better idea than a mobile hot wallet (i.e greenwallet) for small amounts.
Electrum's desktop wallet is a hot wallet (if used as such) just like Greenwallet is. You just run one on a desktop environment and the other on a mobile. They are both good as long as you know what you are doing and can't be tricked easily. If that is not the case, better stick to your HW.