`xsel -ib` has no effect when shell script stdout or stderr is closed with `>&-` or `2>&-`

[flyxyz123]

xsel version 1.2.0
arch linux, 5.15.2-arch1-1

I have a script called test:

#!/bin/sh
echo 'haha' | xsel -ib

If I run test >&- or test 2>&-, string "haha" is not copied to clipboard.

Is it intended? I'm not sure if this is a bug. However, xclip does't have this problem.