Filtering is working fine here.
If your DLC contains several thousands of items you may run into several other issues like websites timing out or crawlers taking a huge amount of time.
Let's assume that the issue is
not caused by any crawler related time wasting processes (apart from maybe Instagram).
Additionally to the "ignore instagram URLs" rule, try the following:
1. Make sure that JD isn't doing anything at this moment.
Then go to Settings -> Advanced Settings -> Search for "do linkcollector link check" -->
DISABLE this
2. Add your DLC - all URLs should get added quite fast (but without any status as JD skips the linkcheck).
Now you can sort your URLs in the LinkGrabber and only keep the stuff you want.
You can let JD perform a manual linkcheck on selected items at any time via Rightclick -> Check online status
In general, you should re-enable the above setting when continuing to use JD as you usually want it to check the links you're adding.
Just in case there is anything you've done wrong, here is a screenshot of a working "filter instagram.com URLs" rule:
-psp-