Perhaps if you used a term like "advised" or "suggested," rather than "lectured," you might have received a different response. I think we got the impression you advocated a single position, "Wait." If you fairly presented the pros and cons of waiting/purchasing now, then I have no issue.
In the world of computers, "There will be an update/new model soon" is the rough equivalent of "The sun rises in the east." Maybe it'll be 50 days (July 28? It's been years since Apple released an iMac at that time of year). It could just as easily be 100 days, or more.
If the current machine is four or five years old, the important performance bump isn't the small one that may come sometime later this year, it's the big one that happens the moment the new machine is removed from the box.
The MacRumors Buyer's Guide approach is interesting, but it doesn't meet my definition of a Buyer's Guide. It's more of a Window Shopper's Guide, or a Non-Buyer's Guide. A Buyer is someone who wants/needs something now, and seeks information to aid in the decision-making process. Of all the products there, there is just one "Buy" and two "Neutrals." Neutral, on a six-month-old, newly-redesigined product??? And if they just glanced and saw, "Don't Buy" and "Caution" without drilling down? They'd think there was something physically wrong with the product. In any worthwhile Buyer's Guide, purchase timing would be just one column among many, not the sole criterion.
Despite the name, an Apple computer isn't a piece of fruit, bound to rot in less than a week. It's a durable item that can be used productively for many years to come.