Armours stand cannot be picked up at all. Trying to interact with them just swaps out the amour as usual. I can pick up other mobs just fine.
I'd like to pick them up for the same reason as chests; to be able to quickly relocate them nearby without having to cluter my inventory.

Minecraft 1.21.4
Fabric Loader 0.16.9
Fabric API 0.110.5
Carry On 2.3.0
No other mod involved

Yes, this is intended. You can remove it from the blacklist if you want to pick them up.

Uh, I did try to remove them from the blacklist, but it turns out there's a bug with the config screen that kept reverting my change:

When I make some changes to the blacklist through the config screen, the changes are immediately written to the config file, but they don't take effect until I restart the game.
If, before restarting, I reopen the config screen, it will show the default blacklist instead of the one written to the config file. Then if I try to change another setting (e.g: maxDistance), this will re-write the default blacklist to the config file, thus completely reverting my changes.

Side question, why are armour stands excluded by default ? They seem like such an obvious thing to pick up for me.