I wouldn't necessarily call it a strawman argument. There are a lot of people that never make it to a fully mature tank just because their intent doesn't allow it. They're constantly trimming coral frags and never giving them the opportunity to fully grow.Do people do that with their display tanks? I haven't met a reefer (in person or on here) who wants to have a display tank full of tiny frags. The tanks permanently full of tiny frags have egg crate and are called "grow out systems" or "frag tanks".
The idea that people have have display/forever tanks full of tiny frags and don't want them to grow in seems like a strawman. That's just not a thing I see at all. I see lots of new tanks with tiny frags which haven't grown in. I see people fragging large mother colonies to make some money on the side. The first of these is just a reality of a new tank, and the second is either for financial reasons or because the colony is too large and shading/overgrowing other, more desirable corals (looking right at you orange monti caps).
There is no "trend" of having display tanks full of tiny frags (on purpose).
And let's quantify what a large mother colony is. I would consider a mother colony at least 12 inches across. And if people are fragging from those then they don't fit the bill that @DanConnor is referring. In my area alone, I can think of 5 people that have been in the hobby long enough to have a fully mature tank. But when I look at them they're full of corals that are on the larger side of what I would still call a frag. The reason is that I can point to facebook posts where they are selling off the pieces that are growing out.
That scenario seems to be a trend inside the facebook underbelly of the hobby (I know that a bit of a dig at facebook). The problem is, they're stuck in this perpetual fragging and selling that they never get to experience a beautiful mature reef.
Not to say there are people fragging because they have to. But those that are fragging because their frag is big enough to cut a piece off has become a popular trend amongst a segment of hobbyists.