No surprise, but apparently, you haven't used expedia or hotels.com lately.
Hotels.com has had it for quite some time. (There are really only 3 companies behind most of the OTA brands out there, and Expedia's a different network.)
I have used both recently, but to book, not to search. I tried hotels.com's EV search when it came out a couple of years ago and found it inadequate. It didn't know about a lot of hotels that had charging. I haven't re-evaluated it in a while, though. No system however lets you book a hotel with *available* charging, which was the context of the message you are quoting. All of them can only find hotels that have some charging. While that's a start, I was saying that someday we want to reserve charging and search for availability. You may have missed that part.
For now, I am forced to go to plugshare. Its listings on charging are the most comprehensive and they tend to have the price and quality of the chargers, which are fairly important. I mean there's a big difference between chargers that rarely work and those that are always available, and a big difference between free to guests and $30, which was the difference in the first example of Springdale UT in the article.
I don't hold much hope on that for the OTAs since it's still hard to search including the price of parking, in spite of that being a very common desire. (When you are coming into a downtown area with a car, it's not unusual for parking to cost a decent fraction of a room night, and you mostly know you are going to need it, though you also want to be told that parking is free on Sundays on the street and you don't need to pay the hotel $25 for it. Sadly few travel apps work for the user so they don't tend to reveal that.)
Update: A quick test of Springdale shows hotels.com only showing 5 hotels with charging: The Marriot Springhill, the Flanigans, the Pioneer, The Hilton Cliffrose and the Cable Mountain. In fact on plugshare it shows 13 hotels, including those 5, plus the campground and visitor center. (There are some RV parks which also could do the job, probably.) That's a huge difference (though a couple may be closed) and suggests the OTAs still don't cut it. Though some day they might.
Hotels.com also doesn't show the Best Western in Springdale, Duke's in Hanksville or The Aarchway in Moab or, the Legacy in Price, which are the hotels I stayed at and where I charged. It did know about Ruby's at Bryce and the Linq in Las Vegas where I stayed, and the Hyatt at SLC at a much higher price than I paid, but that was it. Checking a number of the other hotels I have charged at in hotels.com shows their database is very poor quality, and I am correct not to search with them. (In general, I find google is best for search, other than the fact it shows fake results from bad OTAs and aggregators which you must learn to ignore, but it is much faster than any other, easiest to use, and lets you look across all the major OTAs and direct sites which can save good money.)
In future, please don't talk about me. Discuss the topics I bring up to your heart's content, but never refer to what another poster is or does if you can avoid it.