The "hothousing" topic is a difficult one. Here's one aspect I've been thinking about lately.
It feels like hothousing when the parent is, so to speak, "teaching to the test." When the child is being groomed very specifically to look good on certain narrow criteria and make it through the next hoop. It feels like hothousing when the goal is to push the kid into the next level of whatever, which they are in fact NOT really prepared for or suited for. It makes us feel bad for the kid, and it makes us frustrated that programs get watered down because of this kind of thing.
That's rather a different thing, I think, from insisting on challenge and progress and work ethic from a gifted kid, in matters of genuine intellectual interest or topics that are neccessary for what the kid wants to achieve (like accelerated math for a budding engineer).
