For a network focused on single-family homes, the term McMansion is rarely uttered on HGTV. Here is one example I ran into a few weeks back on My Lottery Dream Home:
On the top left of the image, you can faintly see some of the narration over the image: “Willow Park Way that almost looked like a McMansion.”
Almost a McMansion. The exterior here has some interesting features that might place it in McMansion territory: multiple roof lines, interesting window placement, a large house, in a sprawling Texas community.
Even as the couple did not select this home at the end, it is interesting the term was applied to this home and not the others which also could have been viewed as McMansions. Present a large suburban home with a front meant to impress yet some questionable architectural choices and McMansions may just come to mind.
Why the term McMansion is not used much on HGTV is probably very straight forward: it is not a positive term and does not connote the kind of quality of home the network would like to depict. Whether the McMansion is too large, a teardown, aesthetically unappealing, or connected to sprawl or excessive consumption, few people would likely loudly say they like such a home or live in such a dwelling.
At the same time, this episode was set in suburban Texas where housing tastes are different than in more sophisticated markets. In my comparison of the use of the word McMansion in the New York and Dallas regions, there was more openness in Dallas to such homes and what they represent. Surely, some McMansion dwellers and afficionados watch HGTV and they might be in markets where McMansions are not so disliked.
I will keep checking for more mentions of McMansions on HGTV. As I do, I am much more likely to hear terms like mid-century modern or country farmhouse much more than the term McMansion.