We have two reasons for this:

Firstly, we prefer authentic growth of the instance

and

secondly, there are currently too many known technical issues with the import tool. We'd rather ship this feature when it's ready for action, than put the user experience at risk.

If this feature is very important to you, please write to us with the tag #instapiximport and we'll get back to you and check how we can help.

After the release phase of instapix.org has concluded, we'll take care of more features and also look forward of bringing the import feature in a online with a future Pixelfed release.

Have fun sharing your best shots in the meanwhile!

All the best,
Fediverse Foundation