No choice is made in a vacuum, including the choices to cover most of one's body, or to uncover most of it.
I'm a white, secular woman who dresses 'modestly' (long skirts, long-sleeved tops, high necklines) for aesthetic reasons (I like swishy skirts!), to cover scars, and because as a feminist I'm not interested in catering to the male gaze. I have bought clothing primarily marketed at Muslim women before, because I liked it.
I also recognise the right for other women to cover as much or as little of their bodies as they want. Their choices have nothing to do with me and I don't go around judging how covered (or not) other women are. I do think there is a slight value-judgement embedded in the word 'modest' but it's the most convenient shorthand I have to describe the way I dress. 'Conservative' to me has the connotation of traditional/old-fashioned rather than more covering. In practice, the topic rarely comes up - I think the most recent time was when I was discussing swimwear, where 'modest' can mean anything from a regular swimsuit with a little skirt attached, to a burkini.
I like the idea of this fashion week. I have zero interest in mainstream fashion, but would be interested in taking a look at this. Lots of people won't be interest, but no event is designed to cater to everyone!