Linux is secure?
Linux is vulnerable as any other operating system and users must be informed about this.
Security is not a product.
Security is a process.
There is no "security version 1" or "security version 2beta".
There are only systems that applied a certain well defined policy for their use and for the functioning of the internal components.
Freedom wants you can freely modify these processes by users and therefore the price of safety is freedom.
You give up something to get something else.
Already having to enter a password is lack of freedom, but it guarantees a certain level of security.
The underlying problem of why security is also related to the risk of inadvertent mistakes: this is why you should never use an administrative account to log on to the system during daily use.
Rather, when you need it, you should authenticate with the minimum privileges necessary to install a program or driver, possibly within the same session of previous work and soon after losing these rights.