Hi Chad,
You offered up some serious objections. Yes, certainly kids who had a rocky start can recover. I may have been a little hyperbolic using the word “forever” there. On the other hand, giving a child the best possible start gives them a cumulative advantage. As far as the mechanics of literacy, in fact, with the new emphasis on the Science of Reading, young students are going a lot deeper with learning phonics. Research has shown this to be more effective than memorizing sight words. Finally, you’re right – early exposure at age 3 may not slow down learning at age 6. However, if you are skipping straight to sight words at age 3 and not spending time on phonological awareness skills, then the child who appeared to be an early reader may not actually thrive as fully in the long run as a child who spent more time on these early steps. I think a 3 year old’s time would be better spent listening to read-alouds, playing with language (such as rhyming songs and games), and having lots of opportunities and encouragement to speak and listen.

Has this happened, ever? Kid gets shown some sight words at three and then spends the rest of their life not wanting to read?

“Just because a child can see a word and speak it back to you correctly doesn’t necessarily mean they have a deep understanding of the mechanics of literacy.”

Yes, but we don’t expect even a seven year old to have a “deep understanding of the mechanics of literacy”, nor is that required to read. If a child can read “and” and understands what “and” means what is the impediment to reading?

“Children who start working on sight words too early will tend to acquire those words more slowly. This is because they don’t have the mental literacy framework yet for more rapid learning.”

That’s not to say the child will learn more slowly at age 6 because of early exposure at age 3. Rather learning the same material at age 3 is slower than at 6. But so what, the kid is able to learn more starting at 3 than 6.