Somebody explain to me this:

I am trying to delete items from a list with matching ids contained in another list of strings.

Step 1 is as below:

I'm trying to delete Items from myListingSyncIDs where the ListingNumber matches ListingNumbers in lstListingsUpdatedIn24Hrs.

The item at [0] Equals a value from lstListingsUpdatedIn24Hrs, as shown in Step 2:

But as shown in Step3: The Remove fails:

Then After doing a RemoveAll(func) Step4: The Remove works

Somebody explain why the Remove(item) doesn't work, Please ...

Reference: http://stackoverflow.com/questions/9496474/listtype-remove