I don't think anyone will be able to provide an answer that can help or you'll want to hear, unless it's simply to agree with you. I can understand the frustration in some ways, I'm kinda protective of my pics as they take me the longest out of any listing... thing that needs doing, and if someone told me "it's just part and parcel of the site to have a pic stolen every now and then", I wouldn't be too receptive to that....
.....buuuut..... I'll say this anyway 🙃 eBay is basically becoming a product database, hence why they have catalogue items, images, and pre-filled product-specs. If you submit a product to / on eBay, you are contributing to that catalogue. So, if eBay nabbed one of my pics and whacked it in their product catalogue for other sellers to use forever, I'd just have to take it on the chin.
This is also something pretty common to any community site with user-submitted catalogue-style content. Take Discogs, for example - slightly different scenario because the focus is on creating a database of music releases with as much information about every known issue of a release as possible - people who aren't even selling releases in the marketplace can spend hours every week creating new entries, entering every last detail, taking high quality scans to upload etc (myself once included, like the data nerd I am 🤣), and then a casual seller can just be like "yeah, I'm selling >>this<< one" in 2 seconds and reap the benefits of all that work.
