That’s a bad take. Unless you get your knowledge purely from shady tutorials or have a fast track bootcamp education, it’s unlikely you never touch on security basics.
I’m a software design undergrad and had to take IT Sec classes. Other profs also touched on how to safely handle dependencies and such.
While IT Security is its own specialisation, blindly trusting source code others provide you with is something a good programmer shouldn’t do.
If you need a metaphor: Just because a woodworker specialises in tables, doesn’t mean they can’t build a chair.