You have that right. In the event that keeping first-turn Land Tax offline becomes such a priority that one wants to hold a land drop back to achieve it, that land drop would be the second, and not the first. One could potentially use Mox Diamond to drop first-turn Land Tax and have it active right away. One could use a regular land drop to get mana for Land Tax, but then sacrifice that land to Zuran Orb, enabling Land Tax. There are some other possibilities, but these situations are...
A: Corner cases that wouldn't normally persuade one to avoid a first land drop as a matter of course.
B: Irrelevant in Legacy.
I seem to remember arguing that holding back early land drops is generally a sort of rookie mistake against Land Tax decks. To the uninitiated, it may seem as though allowing Land Tax to trigger would give its controller insurmountable card advantage, and that the only way to play around it would be to wait until the player with Land Tax has more lands out. While it could pay off for a very efficient aggro deck that can churn out threats with only one land, this approach would normally play right into the hands of the Land Tax player. Historically, Land Tax decks were control decks (sometimes with a bit of control-combo thrown in). Holding back land drops to keep Land Tax offline enables the Land Tax player to slow the game down and establish control, winning even without Land Tax against an opponent who is voluntarily forfeiting tempo. On top of that, holding back just one land drop might not be enough, since the Land Tax player could cull lands (as with Zuran Orb) and get Land Tax online again. The reason that Land Tax didn't dominate tournament play even in its own prime was that turning the virtual card advantage from Land Tax into a real board presence took time. The most successful Land Tax decks dug up a bunch of plains, then used Scroll Rack to trade some for business cards, and then played those business cards to keep up a board presence. While the Land Tax player was doing that, the opponent wasn't merely sitting idle, but was presumably trying to win the game. Tax/Rack wasn't a bad engine, and first turn Land Tax into big card advantage in later turns was, in some cases, a force to be reckoned with, but it simply wasn't the case that Land Tax created an environment in which putting out first lands was something to be avoided.
I've made reference to this line by Forsythe because I think it displays a blatantly wrong understanding of a card by a person at WotC who was in a position of making decisions regarding that card's tournament legality. Now, I don't think that Aaron Forsythe is stupid or that he doesn't understand the game. He was a successful tournament player way back when I was new to the game. I know that I've liked some of his work in set design and such. But it seems that he sometimes goes too far in trying to make points about matters he doesn't actually understand. And this was one of those times.