Inconsistently Yours
I doubt anyone is. That's sort of my point. And just as well, an animal behaviorist cannot provide concrete proof of anything. Anecdotal evidence and observed behavior interpreted in some way are only theoretical. We can deduce that a rat seems happiest when with others, but this is not always the case (such as with solo rats who are aggressive to other rats) and this is not proof of anything. It is, again, speculation.
The fact is that a rat is generally best with other rats. I'm not arguing this. What I am saying, is that it is not always in the best interest of the rat, and it is not a necessity. Solo rats who are given adequate human interaction and toys often lead very healthy, happy lives. To overdramatize the 'need' for cage mates is dishonest, especially when applied to a newbie rat owner.
You're making a very reasonable point, and I'm not 100 percent opposed to what you're saying, but personally deep down I just have to disagree. I think for very social animals, they crave same-species interaction and do not flourish as much as they could without it. (this is assuming this is a normal, healthy animal without aggression making it impossible for a companion). Yes, a singly kept rat can live a very long and healthy life, but I don't think they'll reach complete fulfillment when they don't have a companion to groom, to eat with, to make nests with, to just socialize and interact with. I think the need for a companion is as great or even greater as the need for an adequately sized enclosure to have room to exercise or toys and activities for mental enrichment.
Your point is very reasonable, though, and I can respect feeling that way.