I don’t think they mean professionally, but rather being able to create clothing from scratch.

How many people do you know that could turn raw fabric into a dress? I have can do the simplest repairs and even used a sewing machine a few times but that’s not particularly useful to a garment factory.

My daughter has made at least 10 dresses before graduating from high school. She's now progressed into a textiles program at our university. My step-sister made very elaborate dresses for her daughter throughout school as well.

Sewing/dressmaking is a lot like woodworking. Being able to visualize things well in 3D is an asset, but also having good tools helps as well.

Once you have the basics it's just a matter of scaling. Creating clothing isn't hard, creating beautiful clothing, now that's a different matter.