Zacks doesn't make any such claim, in fact Zacks very clearly states that settlement is T+2 and points out that this change happened in 2017.

Directly from the link:

"In 2017, the SEC amended the T+3 settlement cycle to a T+2 settlement cycle, effectively shortening the three-day rule to a two-day rule."

You and I must be reading different documents. You must have navigated elsewhere. Please provide your exact link.

I clearly see the following. Directly from the link of the poster I responded to:

https://finance.zacks.com/tax-rules-use-proceeds-stock-sales... Tax Rules on How to Use Proceeds of Stock Sales to Buy New Stocks

...

For example, imagine that on Monday you have nothing in your brokerage account except shares of a specific stock, which you sell that morning for $10,000. The trade will settle on Thursday.

They just described T+3 not T+2!

It's further down the (infinite-scrolling) page, under the title "Why Wait Three Days to Sell Stock?". Looks like much of the material there is older, but this section at least has been updated to mention the change to T+2.

(Looks like a more direct link would be https://finance.zacks.com/wait-three-days-sell-stock-11114.h...)