I keep seeing this but as far as I can tell the only study on the subject seems to show that it has no effect on their normal grazing patterns and that both domesticated and wild ducks heavily fed bread spend 90% of their time "naturally grazing"
It's basically just duck junk food. https://www.uu.nl/en/background/what-to-feed-ducks-according-to-science Probably not an issue if they don't get too much, and still get plenty of good quality food in. I'd still rather give them something good for them, but I'm glad it's not as terrible as it seems.
Totally agree, it's just that there is a lot of pearl clutching when it comes to this topic and we need a more balanced approach.
A little bit of bread is not going to hurt them, but maybe there are some other options that are better. But if they get fed some bread, probably don't need to have an aggressive confrontation about it