The Linux software you can get as a regular user from your typical Linux distributions is absolutely not any more secure on average than your typical Windows software.
I say this as someone who writes application programs on both systems.
I think it’s really debatable whether the Linux kernel is really any more secure than the Windows NT kernel. Linux advocates have pushed the “many eyes, shallow bugs” line for a long time, but high profile lapses seem to really have put the lie to that.
It used to be that 640K oughta be enough for anyone.