No, that's wrong. Mass-produced clothing is the direct opposite of a commodity.
A commodity would be silk, or cotton - the raw fabric used as base materials. What you then do with those materials to increase their value directly changes them from commodities into products.
Put another way - gold is a commodity, as is silver. Jewelry, however, is not. It can't be a commodity if the material has been changed into a diversified form to increase its value - it has to be raw in order to be a commodity.
No, it's not. Commodities are products with multiple sellers and minimal differentiation. You can only put Ralph Lauren clothes into that bucket by willfully ignoring the concept of differentiation. Meanwhile: there is literally no differentiation between different suppliers of IV saline; it's a standardized product.
When a brand label is reduced to "this is what we put on products our buyer/sourcer has obtained at the lowest cost", you no longer have a design element at work. Increasingly, brands don't designate manufacturer, but middleman (yes, there are exceptions, but they're increasingly, well, exceptional).
Some very high-end custom-designer fashions might be excluded, but if you're buying off-the-rack (or mail-order/online) clothing manufactured in mass, you're buying a commodity, in the sense of a largely undifferentiated item. The label is the _only_ item of distinction (and not even that when you're getting grey-market goods).
Incidentally, look up "commodity" in your dictionary, it doesn't mean what you think it does.
You're just convinced it's not.