Tbh I think theres two things to talk about.

Theres the stretching of the vaginal opening and the stretching of the labia etc on the outside. A big hanging labia isnt indicative of a larger vagina on the inside.

But what I do think is the vagina can stretch. Whether it being due to muscles relaxing and being able to stretch more than previous. Like how you stretch your normal muscles. You dont actually lengthen a muscle when you stretch you just train that muscle so it can function in that extreme and doesn't spasm or tense up as a protective measure.

So yeah, a girl that cant take a big fat thing initially, will be able to eventually. As evidenced by my relationship with my gf for the past 8 years.

What girls get defensive about is the fact people think it has permanently deformed it. Like its saggy and loose. But no it just has a greater range of movement. Call that what you want. But to me it's called stretching. Theres people taking about different things all wrapped up into the same argument.