That doesn’t mean the issue wasn’t/won’t be escalated. It might even mean it’s more likely since someone bothered to make a response macro for it, they presumably got more than one or two emails about it. So it’s probably more likely to make it on a “list of issues we saw this week/sprint/month/quarter”.
This is just a guess, but I’d imagine that happens because the websites use JavaScript to load the actual content of the page, but Lemmy is just parsing the HTML that is returned.
Also, I really doubt you’d have much luck convincing website authors to completely change their architecture just to get previews to work on Lemmy.