Delicate textiles - Lacy and dainty things such as ladies undergarments, blouses, baby things, etc...
Fragile textiles - curtains (especially lace), items that have been well used and laundered previously to point of having tender areas (if not outright holes), some bed and table linen, heirloom linen.
Curtains are most always considered "fragile" due to effects of prolonged sunlight exposure. The item(s) may seem strong enough when taken down, but once in the wash the only thing that was holding them together (hope) sometimes goes; and things just fall apart.
Many commercial laundries routinely advise customers sending in window treatments of the above, and or request a waiver be signed acknowledging such facts. Indeed if you read TOS for many dry cleaners, laundries, etc.. they state will not be held liable (or limited) for damage to tender/fragile items.
Personally wouldn't put any "fragile" textile into a top loader with central beater, but that's just me. In fact am loathe to use most H-axis machines as well, but they are a better option IMHO.