Where are you getting the idea that ALEC is trying to be transparent about about writing these laws? The article is clear that it takes some digging to uncover these bills:

USA TODAY and the Republic found at least 10,000 bills almost entirely copied from model legislation were introduced nationwide in the past eight years, and more than 2,100 of those bills were signed into law.

The investigation examined nearly 1 million bills in all 50 states and Congress using a computer algorithm developed to detect similarities in language. That search – powered by the equivalent of 150 computers that ran nonstop for months – compared known model legislation with bills introduced by lawmakers.

There isn't some tagline "this bill contributed by ALEC!"

FWIW - ALEC does make all their model bills available online: https://www.alec.org/model-policy/

But they are hardly the only player, we were interested in not only identifying how far these known model bills are going but also surface bills from groups we don't know about!

Also, not all model bills are necessarily malicious - we found hundreds of bills that were almost identical but were just trying to standardize things like how we license nurses or other healthcare practitioners.

Right, if you look elsewhere on the thread I've made this point already: the whole idea behind ALEC model legislation is to have it introduced in multiple state houses. There's no similarity search you can run for legislation "authentically" drafted by different congressional offices, and yet it's an article of faith on HN that corrupt bills are authored that way all the time.

  more than 2,100 of those bills were signed into law

In other words, such bills have a failure rate of 78%.