I agree that people have a knee-jerk reaction against poly, and it shows in the article in question. Part of the problem is that a magazine writer has to "speak the readers' language;" that is, talk about things in a way that will please the readers. So if a writer perceives that public opinion is largely opposed to polyamory, that writer will hesitate to say anything good about polyamory.
I just see this particular article as a marker for how far public perception has improved so far. People still have an attitude problem about poly, but they're starting to calm down about it. Enough to admit -- in their own condescending way -- that "some poly families can look normal." It is far from the fair and equal treatment polyamorists and other minorities desire, but it's hopeful to see some popular trends moving in the right direction. I mean, heck, the fact that they're finally talking about us at all is a good sign. Talking can evolve into a dialog, eventually.
I think bad attitudes about polys and homosexuals originate in the Church (and churches). Professionals like psychiatrists answer more to the Church than they'd care to admit. Observe that homosexuality was once officially considered a kind of mental disorder. That is largely how poly is perceived today, but like Darth Vader when he asserted to Luke that "there is no conflict," there is indeed a conflict and some professionals are starting to advocate a new way of looking at polyamory.
I guess it really is a slippery slope. A slope towards acceptance. People are clashing (violently) over whether homosexuals ought to be accepted. I think that each successive generation will see a new level of acceptance. It may take longer for polyamory to gain the same level of acceptance, but it'll happen eventually. I'm content for now to just watch the mile markers go by.
Oh, I guess I'm not as much of an activist as I should be. I'm not even out to the vast majority of my friends and family. But a few people know, more will probably follow, and I can set a quiet example which is what I try to do. And participating in poly groups is helpful because it helps other poly people know that they're not alone.