~snip~
The security advice against using Core as a wallet is that:
2) If you're running Windows.
Windows is terribly insecure so you need to take precautions not to be infected by malware that will steal your bitcoins.
There is no real 'security advice' against using core.
Core is just as secured (regarding malware) as any other desktop wallet.
Additionally its not like if you switch to linux you don't need any security precautions anymore.
The majority of malware is written for windows, yes. But linux is by far not 'secured enough' to be called safe.