What a great thread! As I'm reading, a couple of thoughts that are popping into my mind...
I see the tension around hot housing as primarily related to the impact it has on other parents and kids.
First, kids who teach themselves (by which I mean, they leap to new skills and/or interests with light exposure rather than persistent parent drill) probably have different instructional needs than children who don't. This speaks less to whether or not they are or are not gifted than it does to what they need in order to continue moving forward. Not distinguishing between these different learning styles can really wreak havoc with a parent's attempts to secure appropriate learning conditions for their child and--I think--creates a tense dynamic in which parents of leapers see acheivement scores leading to their children placed with children who may be gifted, but are not leapers. This becomes a big deal because it shapes how instruction is delivered to the detriment of those who "leap".
Unfortunately, parents of kids who are not leapers may view the attempts to distinguish needs as "my-child-is-more-authentically-gifted-than-yours" competitiveness.
Secondly, those who hothouse in a "Tiger Mom" kind of way create a lot of anxiety in some families who would not normally choose to do that. It is the lucky parent indeed who does not worry that they are hurting their child either by pushing to hard or by not pushing enough. When other families adopt an uber "go-go-go" approach to preparing their child for the world, other families may feel pressured to do the same. I don't think that all families have a need to see their child be the best, but most probably experience anxiety if it seems that their children could be left behind. As a parent who wants my kids to enjoy being kids (and as a teacher who thinks we have taken too much recess, creativity and joy out of school), I find that pressure unhealthy, and I have to remind myself to stay true to works for my kids and not worry about what someone else is doing with their kids.
