Eh, it's half-n-half.
One half prefers to keep the idea of giant women free from the potential thoughts of crushing people, while the other half explicitly enjoys detailed portrayals of people getting crushed to death.
I know because of Pixiv.
(If you're wondering what my own preference is, as a person with a strong aversion to death and gore in porn, I'm definitely in the first group.)

Dynamaxing is pretty much a macrophiliac's excuse to draw art and not be considered weird about it.