I agree, under normal operations always feed from a magazine.
However, few auto pistols will feed empty brass and this brass was not only empty (we hope it had been broken down), it had high primers. Slamming the slide forward can lead to 'follow down'. But, 20 or so times... Hopefully the primer would be seated deeper. At the worst, it would be a slam fire and would impress the need to have primers fully seated.
I have only encountered one broken extractor (the break was on the rear half) and that was a 'stainless steel' one in a 'Vega' (they were all stainless, I never thought much of them. It wasn't mine. They were a pita, nothing lined up and everything had to be fitted. Haven't seen one in 30, maybe 40 years. No loss). I did have a chipped extractor come in one time, but, the extractor still worked and the owner didn't want to replace it.
I would hope that any blue/carbon steel spring steel 1911 extractor will hold up to this small amount of abuse. If not, this is the time to find out.
Load with care,